JPH02137838A - Variable magnification device in image input device - Google Patents

Abstract

PURPOSE:To accurately move a light guiding means to a desired position without returning it to a reference position for each alteration of magnification by distinguishing the position of the light guiding means based on the output of a detecting means fitted to the means. CONSTITUTION:A variably magnifying device for an image input device has the light guiding means 19, the detecting means 43, and a detected means 44, the means 19 is capable of moving in the optical path of light reflected from an illuminator which has illuminated an original, the means 43 is fitted to the light guiding means 19 and moves together with the movement of the light guiding means 19, the means 44 is arranged so that it is hardly affected by the movement of the light guiding means 19. The detected means 44 is provided with a switching position B, which switches the condition of the detecting means 43, along the moving direction of the light guiding means 19. The light guiding means 19 is moved, and the position of the means 19 is distinguished based on the amount of its movement from the completion of switching the condition of the detecting means 43 to the subsequent completion of switching. Thus, the position of the light guiding means 19 can be detected, and based on the result the means 19 can be accurately moved to the desired position.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a variable magnification device for an image input device, such as a variable magnification device for a copying machine.

<Prior Art> Copying machines having a zoom function are known. In this type of copying machine, a document is generally illuminated with an illumination device, and the reflected light is used as an image input signal. A condensing lens and a reflecting mirror are provided in the optical path of the reflected light as light guiding means, and by moving the condensing lens and reflecting mirror, the image input device can be adjusted to a desired magnification ratio. .

In addition, in order to accurately move the light guiding means to a desired variable magnification position, a reference position called a home position is usually provided, and before moving the light guiding means to a desired variable magnification position,
The light guiding means was always returned to this reference position and moved to a desired position with reference to the reference position.

In the conventional device, detection of whether the light guide means has reached the reference position is performed by, for example, a photosensor provided on the light guide means and a shielding plate placed at the reference position.

<Problem to be solved by the invention> However, with modern copying machines, for example, 50% to 200%
9'6, the range of variable magnification has become extremely wide, and the moving distance of the light guide means has also become longer. Therefore, if the light guide means is always returned to the reference position before being moved to the desired magnification ratio position, it becomes a problem that it takes time to move the light guide means.

On the other hand, if the movement control is repeated without returning the light guiding means to the reference position, the stop position of the light guiding means will deviate from the desired position because there will always be mechanical errors due to the configuration of the variable magnification device. There is a risk that the copy may be out of focus or the copy may have a different magnification ratio than the desired one.

This invention was made to solve this problem, and it is possible to detect the position of the light guide means without returning the light guide means to the reference position every time variable power is controlled, and to detect the position of the light guide means based on the detected position. An object of the present invention is to provide a variable magnification device that can accurately move an image to a desired position.

Means for Solving the Problems> The present invention provides a variable magnification device in an image input device that illuminates a document with an illumination device and uses the reflected light as an image input signal, the magnification changing device a pair of detecting means and a detected means that are attached to the light guiding means and move as the light guiding means moves; and movement of the light guiding means. The sensing means and the other of the pair of sensing means are fixedly disposed relative to each other. a plurality of switching positions are arranged for switching the state of the sensing means; further, the light guiding means is moved and the state of the sensing means is switched from one time to the next time the light guiding means is moved; A variable magnification device for a human-powered image device, comprising: a position determining device that determines the position of the light guide device based on the amount of movement of the light guiding device.

Effect> When the light guiding means (for example, a condensing lens and a reflecting mirror) is moved, the relative positional relationship between the detecting means and the detected means changes. Since the switching positions are sequentially arranged at different distances in the detection means, the output of the detection means is switched every time the detection means detects the switching position. The intervals between each switching position are sequentially different, so if you memorize the intervals in advance and compare them with the amount of movement from one time the sensing means switches to the next, you can determine the difference between the sensing means and the detected means. You can grasp relative positional relationships. Since either the detecting means or the detected means is fixed, the position of the light guiding means to which the detecting means or the detected means is attached can be determined based on the output of the detecting means.

<Embodiment> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is an illustrative view of an image input device portion of a copying machine in which an embodiment of the present invention is adopted. A contact glass 12 for setting a document is arranged on the top surface of the body 11 of the copying machine, and a document cover 13 for covering the document is provided on the contact glass 12 so as to be openable and closable.

Inside the body 11, a lighting device 15 for illuminating the original 14 set on the contact glass 12, and an original 1 are provided.
Reflector 16.17 for reflecting the light reflected by 4.
18. A condenser lens 19 for condensing the reflected light and a reflection f for guiding the condensed reflected light to the photosensitive drum 20
i21, 22°23 are provided. Photosensitive drum 2
0 is exposed to the guided reflected light, and an electrostatic latent image is formed.

The lighting device 15 and the reflecting mirror 16 are connected to the lighting device unit 2.
4 and move in the direction of arrow A1,
The document 14 can be illuminated from its leading edge to its trailing edge. The reflecting mirrors 17 and 18 are attached to a common mirror frame 25, and follow the movement of the illumination device unit 24 in the A1 direction, and move a distance equal to one-half of the illumination device unit 24. As a result, the optical path length of the light reflected by the original 14 until it reaches the condenser lens 19 is kept constant. Reflecting mirrors 21 and 22 are also attached to a common mirror frame 26.

In this configuration, in order to change the size of the image formed on the photoreceptor drum 20, it is necessary to
What is necessary is to change the ratio of the optical path length from 9 to the photoreceptor drum 20. Therefore, in this embodiment, the condensing lens 19 is movable in the optical path to the upstream side (left side in the figure) and downstream side (right side in the figure) as shown by arrow A2, and the reflecting mirror 21 The mirror frame 26 to which the mirrors 22 and 22 are attached is also movable upstream and downstream as shown by arrow A3.

FIG. 1 is a plan view showing the arrangement relationship between the condenser lens 19 and the mirror frame 26 and the mechanism for moving them. The condensing lens 19 is mounted on a lens mount 27. The lens mount 27 is guided by two guide rails 28 and 29 and is movable in the left and right directions as shown by arrow A2.

A wire 3o is stretched parallel to the guide rail 28.

A wire 30 is stretched between pulleys 31 and 32, and a portion of the wire 30 is connected to the lens mount 27. Further, the wire 3o is wound around the driving pulley 33 several times. The drive pulley 33 is connected to a stepping motor 35 by a gear mechanism 34. Therefore, the rotational force of the stepping motor 35 is applied to the driving pulley 3 by the gear mechanism 34.
3, and when the drive pulley 33 rotates, the wire 3
0 moves in the direction of arrow A4, and the lens mount 27 is guided by the guide rails 28 and 29. In addition, when moving the condensing lens 19 (lens mount 27) upstream (to the left in the figure), the stepping motor 35 is rotated in the forward direction, and when moving in the opposite direction, the stepping motor 35 is rotated in the reverse direction. There is.

The mirror frame 26, on which the reflectors 21, 22 (not shown in FIG. 1) are attached, also has two guide rails 37.
38, it can move left and right as shown by arrow A3. The mirror frame 26 has a protrusion 39 at one end thereof.
is provided, and a rotatable engagement roller 40 is provided on this protrusion 39.
is provided. The engagement roller 40 and the gear mechanism 34 are connected by a cam 36. Therefore, not only the driving pulley 33 but also the cam 36 is rotated by the stepping motor 35, and the mirror frame 26 is moved. That is, when the desired magnification ratio is set, if the lens mount 27 is moved to move the condensing lens 19 to a corresponding position, the mirror frame 26 is also moved to a predetermined position accordingly.

A mounting piece 42 extends from one end of the lens mount 27, and a photosensor 43 is attached to the mounting piece 42. The photosensor 43 includes, for example, a light projecting element 43a and a light receiving element 43b. The photosensor 43 derives an "L" output or an "H" output depending on whether the light from the light projecting element 43a to the light receiving element 43b is blocked. Also,
A shielding plate 44 is provided as a detected means paired with the photosensor 43.

The shielding plate 44 is like the photosensor 43.
For example, it is attached and fixed to a body frame (not shown). The shielding plate 44 is a longitudinal member extending parallel to the guide rail 29 and has approximately the same length as the guide rail 29. The upper edge of the shielding plate 44 has irregularities alternately formed in a rectangular pulse shape, as can be seen from the side view indicated by B surrounded by a dashed-dotted line in FIG. When these convex portions are located between the light emitting element 43a and the light receiving element 43b, the output of the photosensor 43 becomes L'', and when the recessed portions are located between the light emitting element 43 and the light receiving element 43b, the output of the photosensor 43 becomes L''. 43 becomes "H".The convex portions and the concave portions have mutually different widths (dimensions along the longitudinal direction of the shielding plate 44).From another perspective,
The boundaries between the convex portion and the concave portion, which serve as switching positions for switching the output of the photosensor 43, are set at different distances 41, 72, . j3. j4
゜45,! 6. They are placed across J7. and,
In this embodiment, the switching positions are 50% from the right.
, 70%, 81%, 100%, 115%, 141%, 1
73% and 200%, and when the output of the photosensor 43 is switched at each switching position, the condenser lens 19
The position is set to be the position of the above magnification ratio.

In this way, the magnification ratio of each switching position is set to a relatively frequently used magnification ratio, but it goes without saying that other values may be used.

Furthermore, in this embodiment, the switching position on the shielding plate 44 is defined by the boundary line between the convex portion and the concave portion.

However, a very thin slit may be formed in the shielding plate 44, and the switching position may be defined by the slit.

Furthermore, in this embodiment, the photosensor 43 is attached to one end of the lens mount 27 to make the photosensor 43 movable, and the shielding plate 44 is fixed. It may move together with the stand 27 and the photosensor 43 may be fixed.

FIG. 3 is a block diagram of a control circuit of the variable magnification device shown in FIGS. 1 and 2. FIG. The control circuit is CPU46, CP
It includes a ROM 47 in which a control program for the U 46 is stored, a readable/writable RAM 48, and an input/output interface 50, which are connected by a bus 49. The output of the photosensor 43 mentioned above is given to the CPU 46 via the input/output interface 50, and
A motor drive pulse from the CPU 46 is applied to a drive circuit (not shown) for the stepping motor 35. RAM4
8, a flag F for indicating the rotational direction of the stepping motor 35, a counter for counting the number of motor drive pulses applied to the stepping motor 35, and a relative positional relationship between the photosensor 43 and the shielding plate 44. 41. J2. ...An area where the number of motor drive pulses required to move Noah each distance is stored in advance, an area where position data Dpst is stored, an area where the number of drive pulses Dsub required for movement is stored, a work area, etc. is provided.

4, 5A, and 5B are flowcharts showing the operation of the control circuit of FIG. 3, and in particular, FIG.
It shows the initial control for checking the current position of the condensing lens 19, and FIGS. 5A and 5B show the control for moving the condensing lens 19 to a desired variable magnification position.

First, with reference to FIGS. 1 to 4, the condenser lens 19
We will explain the initial control for checking the current position of. When the power is turned on, the CPU 46
Set the flag F of g to "1"R (step S1), output the motor drive pulse,
Rotate the stepping motor 35 in the normal direction (step S2)
. When the flag F is ']'', it indicates the forward rotation of the motor R-2, and when it is "0", it indicates the reverse rotation of the motor.

While rotating the stepping motor 35 in the normal direction (step S
2) The CPU 46 detects the input from the photosensor 43 (step S3). When it is detected that the input from the photosensor 43 has been switched, it clears the counter in the RAM 4g (step S4) and starts counting the number of motor drive pulses being output (step S5.
6).

For convenience of explanation, in this embodiment, it is assumed that when one motor drive pulse is output from the CPU 46, the stepping motor 35 is rotated by one step angle, and the condensing lens 19 is moved by 1%.

When determining that the input from the photosensor 43 has been switched (step S7), the CPU 46 sets the count value of the counter as Dint in the work area (step S8). This Dint is the distance required for the photosensor 43 to move the distance from a certain switching position to a switching position on the left in FIG. 1, for example, a distance J1 from a 50% switching position to a 70% switching position. It represents the number of motor drive pulses. Based on this number of motor drive pulses, the current position of the photosensor 43, that is, the current position of the condenser lens 19, can be detected as follows.

Explaining along the flowchart, in step S9,
Dint is compared with the number of motor drive pulses required to move the distance 11 stored in the RAM 48. D
If the number of pulses is int-41 (70-50-20), the condenser lens 19 is currently at the 70% position, so
The position data Dpst-70 is set in the RAM 48 (step 510), and the initial control is completed.

If Dint does not match the number of pulses (20) of 11,
Next, Dint is compared with the number of pulses of 12 (81-70-11) (step 511).

As a result of the comparison, if the two match, the position data Dps
t=81 is set in the RAM 48 (step 512).

If they do not match, in the same way as above, p
int and the number of pulses of J3 (100-81-19),
J4 pulse number (115-100-15), J5 pulse number (141-115-26), J6 pulse number (17
3-141-32), J7 pulse number (200-173
-27), and if there is a match, the position data Dps is stored in the RAM 48 at that point.
Set the corresponding magnification ratio as t (step 813゜5
14).

If Dint does not match any of the pulse numbers J1 to J7, abnormality processing is performed (step 515).
, end the control.

Next, FIGS. 1 to 3 and FIGS. 5A and 5
Drive control during zooming will be described with reference to Figure B.

When the CPU 46 determines that the magnification is to be changed (step 521
), the given scaling value Dn is compared with the position data Dpst set in the RAM 48 (step 822).
, for example, at Dn-115[%], Dpst=115
In this case, the CPU 46 ends the control without moving the condenser lens 19 because the current position where the condenser lens 19 is stopped is the position of the given magnification value.

If Dn and Dpst do not match, the CPU 46 compares their sizes (step 823).

For example, if it is Dn-121 or Dpst-115, the control proceeds to step S24, and the CPU 46 sets the flag FF.
Determine the state of R. If the variable magnification control is to be performed for the first time, the flag F is set to 41'' by the R initial control shown in FIG. 5, so the control proceeds to step S25.

Here, CF'U46 is the number of drive pulses Dsub-Dn
-Dpst is determined (step 525).

In this example, it is Dsubm6.

Next, the CPU 46 causes the stepping motor 35 to rotate forward by the determined number of drive pulses Dsub (step S2).
6-528). At this time, it is also detected whether or not the human power from the photosensor 43 is switched (step 530). In this example, since the input from the photosensor 43 is not switched, the input from the photosensor 43 is not changed at the time when Dsub-〇 is determined (step 828).
), the driving of the stepping motor 35 is stopped. Therefore, the condenser lens 19 is at a position where the magnification ratio is 121%.

Then, in step 52, the CPU 46 re-sets the magnification value Dn-121 at that time as the position data Dpst.
9), Finish the control.

In step S30, when determining that the input from the photosensor 43 has been switched, the CPU 46
It is determined between which switching positions the position data Dpst set to 8 is located (step S31.533, 5
35). Then, based on the result, new position data Dpst is set (steps S32, S34, 536
).

After that, the process from step S25 is repeated. Therefore, there is an advantage that movement to a given magnification value Dn is always performed accurately based on a certain switching position.

Note that step S31. S33. In S35, if Dpst is not included in any range, abnormality processing is performed (step 537).

In this way, when the flag F-1 indicates normal rotation of the stepping R motor 35, if the stepping motor 35 is to be rotated in the normal direction, it is driven as is.

However, if flag F-0 indicates that the steering motor 35 is in reverse direction,
As described below, control is performed in consideration of backlash of the stepping motor 35.

Specifically, in step S24, the flag F
-0, control proceeds to step 838 and sets flag F-1. Next, the FR CPU 46 causes the stepping motor 35 to rotate forward until the input from the photosensor 43 is switched (step S
39,540). Then, it is determined between which switching positions the position data Dpst set in the RAM 48 is located (steps S41, S43, and 545). Based on the determination result, Dpst is newly set (step S42
．． S44.546). If Dpst is not included in any range, abnormal processing is performed (step 54).
7).

Next, the CPU 46 compares the given magnification change position Dn and the reset position data Dpst in step 94.
8) If the two match, the current position where the condensing lens is stopped is the desired magnification ratio position, and the control ends immediately.

If Dn and Dpst do not match, compare their magnitudes (step 549); if Dn<Dpst, then
Control is performed from step S25.

On the other hand, if Dn<Dps t, the CPU 46 outputs the motor drive pulse 'X' to drive the stepping motor 35.
is rotated forward by X steps (step 550), the position data Dps t-Dps is corrected to 10X (step 551), and the flag FFR-0 is corrected (step 552).
). The control in steps S50, S51, and S52 takes into consideration the backlash of the stepping motor 35, and "X" is selected to have a larger number of pulses than the backlash.

In step 823, if the given magnification change position Dn is smaller than the position data Dpst, the stepping motor 35
must be reversed. Therefore, the control proceeds to step 353, where the CPU 46 determines the state of the flag F, and if FRFR is F-0, the stepping motor 35 was reversed in the previous operation, so the variable magnification control continues from step S54. I do. Further, even after the process in step S52 is completed, the process in step S
The magnification is controlled from 54.

In step S54, the number of drive pulses DsubmDn-D
pst is determined, and then the stepping motor 35 is reversed by the determined Dsub (steps S55 to
557). At this time, the CPU 46 also detects whether the input from the photosensor 43 is switched (step 55).
9). The input from the photo sensor does not switch, and Dsub
=O (step 557), the CPU 46 sets the variable magnification position Dn as the position data Dpst (step 358), and ends the control.

In step S59, when the CPU 46 determines that the input from the photosensor 43 has been switched, the RAM 4
It is determined between which switching positions the position data Dpst set to 8 is located in step S60. S62,56
4) Based on the results, new position data Dpst
is set (steps S61, S63, 565). After that, the process from step S54 is repeated. Also,
If Dpst is not included in any range, abnormality processing is performed (step 566).

In step 853, if the flag F-1 is FR, the CPU 46 changes the flag to F-0 (step R867), and reverses the stepping motor 35 until the input from the photosensor 43 is switched (step 368).
, 569). Then, in step S70, it is determined between which switching positions the position data Dpst set in the RAM 48 is located. S72.574) Based on the result, new position data Dpst is set (Step S72.574).
71. S73.575). If Dpst is not between any switching positions, abnormality processing is performed (step 576).
.

After resetting the position data Dpst in this way,
The given magnification change position Dn and position data Dpst are compared, and if they match (step 577), the control ends. If Dn>Dpst (step 5
78), the control operations from step S54 are performed. Conversely, if Dn>Dpst (step 578), taking into account the backlash of the stepping motor 35, the motor drive pulse is output by X, and the stepping motor 35
is reversed by X steps (step 579), and Dps t
-Dps t-X is corrected in step 580), flag F-1 is corrected in step SR81), and control from step S25 is performed.

<Effects of the Invention> Since the present invention is configured as described above, there is no need to return the light guide means such as a condenser lens or a reflecting mirror to the reference position every time variable power is controlled. Further, the position of the light guide means can be detected without returning to the reference position, and the light guide means can be accurately moved to a desired position based on the result.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of a variable magnification device according to an embodiment of the present invention. FIG. 2 is a partial schematic diagram of a copying machine equipped with an embodiment of the present invention. FIG. 3 is a control circuit block diagram of a variable magnification device according to an embodiment of the present invention. 4, 5A, and 5B are flowcharts showing the operation of the control circuit of FIG. 3. In the figure, 19...condensing lens, 21.22...
Reflector, 26... Mirror frame, 27... Lens mounting base, 35... Stepping motor, 43... Photo sensor, 44... Shielding plate, 46... CPU, 48...
- Indicates RAM.

Claims (1)

[Scope of Claims] 1. A variable magnification device in an image input device that illuminates a document with an illumination device and uses the reflected light as an image input signal, the variable magnification device being movable in the optical path of the reflected light. a light guide means; one of a pair of detecting means and detected means that is attached to the light guide means and moves as the light guide means moves; and a member that is fixed relative to the movement of the light guide means. the sensing means and the other of the pair of sensing means disposed in the sensing means, and the sensing means includes the sensing means sequentially separated by different distances along the moving direction of the light guiding means. a plurality of switching positions are provided for switching between the states of the light guiding means, and the light guiding means is moved and the sensing means is moved based on the amount of movement from one time to the next time the state of the sensing means is changed. A variable magnification device for an image input device, comprising: a position determining means for determining the position of the light guiding means.