JPH0816768B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image forming apparatus such as a copying machine with a variable magnification function.

2. Description of the Related Art In recent years, many types of copying machines capable of reducing or enlarging copies have come into practical use.

The basic operating principle of a copying machine will be explained with reference to Figure 1. A scanning unit consisting of an exposure lamp b and a mirror c scans an original A placed on an original table a, and the reflected light is guided via mirrors d and e, a lens f, and a mirror g to a rotating photosensitive drum h, which has been uniformly charged in advance, thereby forming an electrostatic latent image on the photosensitive drum h. Next, the electrostatic latent image on the photosensitive drum h is developed, and this visible image (developer image) is transferred to paper P, completing one copy.

At this time, the size of the copy produced in the scanning direction is determined by the relative ratio (hereinafter referred to as the speed ratio) between the scanning speed and the rotational speed of the photosensitive drum h, and the size in the direction perpendicular to the scanning direction is determined by the ratio (hereinafter referred to as the optical path length ratio) between the optical path length from the original A to the lens f and the optical path length from the lens f to the photosensitive drum h.

Therefore, by changing the speed ratio and the optical path length ratio, it is possible to copy the original A at any desired reduction or enlargement ratio.

(Problem to be solved by the invention) However, in the past, the means for changing the optical path length ratio would start operating as soon as the magnification input was completed. Also, since the magnification could not be changed while the means for changing the optical path length ratio was operating, it took a long time to reach the desired magnification if the magnification was input incorrectly or if the magnification change key was pressed by mistake when a change in magnification was not required. Furthermore, in devices in which the magnification can be changed by continuously operating the means for setting an arbitrary magnification, there was a drawback in that it took a long time to finish inputting the magnification if the means for changing the optical path length ratio started operating before the desired magnification was set.

Furthermore, in some copying machines, if the magnification is changed again while it has already been changed, all units must be returned to their home positions and then moved to the desired magnification setting position, which takes a great deal of time.

The present invention has been made in view of the above circumstances, and its object is to provide an image forming apparatus which has a variable magnification function, is equipped with a movable magnification changing member so that the magnification can be changed by a magnification setting operation from a magnification setting means, and is capable of quickly forming an image at a desired magnification.

[Configuration of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides an image forming apparatus having a magnification changing function and including a magnification changing member that is movable so as to be able to change the magnification by a magnification setting operation from a magnification setting means, wherein while the magnification changing member is moving to a first position corresponding to a first magnification set by the magnification setting means, the first magnification is changed by the magnification setting means.
The magnification change device is configured to include a stop means for immediately stopping the movement of the magnification change member to the first position when a second magnification different from the first magnification is set, a timer means for measuring the passage of a predetermined time, a confirmation means for confirming that a third magnification different from the second magnification has been set by the magnification setting means while the movement of the magnification change member is stopped by the stop means, and a means for moving the magnification change member to a position corresponding to the second magnification if the confirmation means does not confirm that the third magnification has been set during the period from when the second magnification is set by the magnification setting means and the movement of the magnification change member is stopped by the stop means until the timer means measures that the predetermined time has elapsed.

(Function) That is, according to the above configuration, in an image forming apparatus which changes the magnification of an original to form an image, if a magnification is input from the magnification setting means while the magnification change member is moving, the movement of the magnification change member can be stopped, thereby preventing the magnification change member from moving unnecessarily and making it possible to quickly obtain an image at the desired magnification.

(Embodiment) An embodiment of the present invention will be described below with reference to Figures 2 to 8. Figure 2 shows the general configuration of a copying machine, in which 1 is a copying machine main body, and a document table 2 is fixed to the top surface of this copying machine main body 1.
The original A set on the top is exposed by the exposure lamp 3 and mirror
Mirrors 4, 5, and 6 are configured to reciprocate along the underside of document table 2 in the direction of the arrows in the drawing, so that exposure scanning occurs during the forward movement. In this case, mirrors 5 and 6 move at half the speed of mirror 4 so as to maintain a constant optical path length. Light reflected from document A by exposure lamp 3 is reflected by mirrors 4, 5, and 6, passes through lens 7, and is further reflected by mirror 8 and directed to photosensitive drum 9 as an image carrier, and the image of the document is transferred to photosensitive drum 9.
The exposure lamp 3, mirrors 4, 5, and 6, lens 7, and mirror 8 constitute an optical system 10.

The photosensitive drum 9 rotates in the direction of the arrow in the drawing, and first the surface charge is removed by a discharging lamp 11, then the surface is charged by a charging charger 12, and then the image of the original A is exposed to light through a slit to form an electrostatic latent image, which is then visualized by the application of toner by a developing device 13.
A paper feeder 14 is provided at the front end of the photosensitive drum 9 for feeding paper P to below the photosensitive drum 9. The paper feeder 14 is detachably attached to the side of the main body 1 and is provided with two upper and lower paper feed cassettes 15, 16 each storing a plurality of sheets of paper P, and paper feed rollers 17, 18 for taking out the sheets of paper P one by one from the paper feed cassettes 15, 16.
The sheet feeder 10 is provided with aligning rollers 19 and 20 for positioning the leading edge of the sheet P fed from the sheet feeder 10 and for conveying the sheet P.

The paper P conveyed by the aligning rollers 19 and 20 is sent to the transfer section.
The transfer charger 21 is in close contact with the surface of the photosensitive drum 9, and the toner image on the photosensitive drum 9 is transferred by the action of the charger 21. After transfer, the photosensitive drum 9 is neutralized by a neutralization charger 22, and then residual toner is removed by a cleaning device 23, returning it to its initial state. Meanwhile, the paper P after transfer is peeled from the photosensitive drum 9 by the action of a peeling charger 24, and then transported to a fixing device 26 by a transport device 25. The transport device 25 is composed of a negative pressure chamber 27 and a perforated belt 28 wound between rollers. The paper P transported to the fixing device 26 has the transferred visible image fixed by a heat roller 29 and a pressure roller 30. The fixed paper P is then ejected by paper ejection rollers 31 and 32.
The paper is then ejected onto an external paper ejection tray 33 by the ejection tray 33.

Furthermore, when a reduced or enlarged copy is desired, the copy magnification is designated via a fourth means 35 as a magnification setting means for designating the copy magnification, which is provided on a control panel 34 described later, and this controls a magnification changing means consisting of a first means 36 for scanning the original A, a second means 37 for changing the optical path length, and a third means 38 for driving the photosensitive drum 9.

The relative ratio (speed ratio) between the moving speed (scanning speed) of the exposure lamp 3 and mirror 4 and the rotational speed of the photosensitive drum 9 is changed to change the size in the scanning direction, and the second carriage 41 carrying mirrors 5 and 6 and the lens 7 are moved to change the ratio (optical path length ratio) between the optical path length from the original A to the lens 7 and the optical path length from the lens 7 to the photosensitive drum 9, thereby changing the size in the direction perpendicular to the scanning direction, thereby obtaining a copy of the specified size. Next, referring to Figure 3, the mechanism involved in changing the speed ratio and the optical path length ratio, which are essential aspects of this invention, will be explained. Figure 3 is a rear view of the copying machine shown in Figure 2 with the original table 2 removed. In the figure, 40 denotes the first carriage, which carries the exposure lamp 3 and mirror 4, which constitute the second means 36 for scanning the original A. Also, 41
denotes a second carriage, and this second carriage 41 is equipped with mirrors 5 and 6. The second carriage 41 is driven by a scanning motor 42 via a mechanism that moves at half the speed of the first carriage 40.

4, the first and second carriages 40, 41 are guided so as to be freely reciprocable by a guide shaft 43 and a guide rail 44. One end of the guide shaft 43 is provided with a drive pulley 45 driven by a scanning motor 42, and the other end is provided with a driven pulley 46.
are arranged, and a toothed belt 47 is stretched through these pulleys 45 and 46. One point of this toothed belt 47 is fixed to a fixing portion 40a projecting from the first carriage 40.

On the other hand, pulleys 48 and 49 are set on the guide support portion 41a of the guide shaft 43 of the second carriage 41, and a wire 50 is connected to the pulleys 48 and 49.
One end of the wire 50 is connected to a fixing member 51.
The other end is connected to the fixing member 51 via a spring 52.
and one point of the wire 50 is clamped to the fixed portion 40a of the first carriage 40. As a result, the pulleys 48 and 49 function as movable pulleys, so that the second carriage 41 is moved relative to the first carriage 40.
can move at half speed.

The lower end of the fixed member 51 is provided with a mirror movement motor.
A rack (not shown) is formed which meshes with a pinion 54 driven by the mirror moving motor 53, and by driving the mirror moving motor 53, only the second carriage 41 can be moved.

As shown in FIGS. 3 and 5, the lens 7
is held by a lens block 55, and this lens block 55 is fixed to the cam follower part 56,
The lens block 55 is connected to a grooved camshaft 58 driven by a lens movement motor 57, and moves forward or backward depending on the direction of rotation of the lens movement motor 57. The second carriage 41 moves in synchronization with the movement of the lens block 55, and these two components constitute the third means 37 for changing the optical path length. Figure 5 shows how the cam follower portion 56 and the camshaft 58 are connected, and the cam follower fitted into the cam follower portion 56
59 moves along the groove of the camshaft 58, so the entire lens block 55 can move.

As shown in FIG. 3, the photosensitive drum 9 is driven by a dedicated drum drive motor 60 as a third means 38 for driving the photosensitive drum 9, separate from the scanning motor 42, mirror movement motor 53, and lens movement motor 57, and these four motors 42, 53, 57, and 60 are each controlled independently.

6 shows the control panel 34 operated by the user, and comprises a print button 61 for instructing the start of copying, a magnification setting button 62 for setting a specific copy magnification, a lamp 82 for indicating that the specific magnification has been selected, a magnification setting button 80 for setting an arbitrary copy magnification, a display 81 for displaying the set magnifications including the specific magnification, a numeric keypad 63 for specifying the number of copies, a display 64 for displaying the input number, a power switch 65, a copy density adjustment section 66, etc. The magnification setting buttons 62, 80, the lamp 82, and the display 81 constitute a fourth means 35 for specifying the copy magnification.

In a copying machine configured in this way, the user sets the copy magnification by operating the magnification setting button 62 or 80 before pressing the print button 61. First, when making a copy at a predetermined specific magnification, the user presses the button of the desired magnification from among the specific magnification buttons 62. In response to this, the corresponding lamp is selected from the lamps 82 and lights up to indicate that a specific magnification has been selected, and at the same time, the copy magnification is displayed on the display unit 81. Also, when a specific magnification is desired, the user presses the magnification setting button 62 or 80.
The currently set copy magnification is displayed on the display unit 81, so if you want to enlarge the image further than this set magnification, press the magnification setting button 80a.
If you want to reduce the image further, press the magnification setting button
Then, if both the magnification setting buttons 80a and 80b are pressed within a certain period of time (1 second in this embodiment),
In this case, the display content of the display unit 81 increases or decreases by the minimum magnification that can be changed each time the button is pressed.
If the pressing time exceeds a certain time (1 second in this embodiment), the input of the set magnification speeds up (increases or decreases at a rate of 10 percent per second in this embodiment), and it is displayed sequentially on the display unit.
The newly set copy magnification is displayed on the display 81, and the moment the magnification setting button 80 is released, the newly set copy magnification is established. And, including this process, whenever the content of the display 81 matches a predetermined specific magnification, the lamp 82 corresponding to that specific magnification is lit. After setting the copy magnification, the user inputs the desired number of copies using the numeric keypad 63, and then presses the print button 61.
The numerical values entered through the input terminal 61 are successively displayed on the display unit 64, so that the user can determine whether or not he or she has entered the values correctly.

In the above description, it has been explained that a specific magnification is selected appropriately using the magnification setting button 62, but it goes without saying that it can also be set using the magnification setting button 80.

In addition, with this copier, you can press the print button without specifying the magnification or the number of copies.
It is also possible to press 61, in which case the copier will
The number of copies displayed on the display unit 64 is copied at a magnification of 81. If the print button 61 is not pressed within a certain time (30 seconds in this embodiment) after the previous copy, the set magnification will return to the same magnification and the number of copies will return to 1.

Now, once the copy magnification is determined, the display 64 will say "READY"
is turned off, and the lens movement motor 57 and mirror movement motor 53 are operated to change the magnification in the direction perpendicular to the scanning direction, and the lens block 55 and second carriage 41 are moved to positions where the ratio of the optical path length from the document A to the lens 7 to the optical path length from the lens 7 to the photosensitive drum 9, i.e., the optical path length ratio, is equal to the specified magnification. In this case, the longest or shortest optical path length is determined by the physical size of the copying machine. Also, since the same lens 7 is always used, the position of the lens 7 can be uniquely determined, and for example, a microcomputer can be used for control, and the lens movement motor 57,
If a pulse motor is used for the mirror moving motor 53, the amount of movement can be calculated very easily, and the position can be determined accurately by counting the number of pulses.

On the other hand, when the print button 61 is pressed, the document A placed on the document table 2 is scanned as the first carriage 40 moves, and an electrostatic latent image is formed on the photosensitive drum 9, and this process is as described above. In this case, the magnification in the scanning direction is determined by the speed ratio between the first carriage 40 and the photosensitive drum 9.
The scanning motor 42 and the drum drive motor 60 are each provided with an independent motor for driving the scanning motor 42 and the drum drive motor 60, so that the speed ratio can be made to match the set magnification by controlling the rotation speed of each motor. The scanning motor 42 and the drum drive motor 60 are both pulse motors, and the number of pulses given to the scanning motor 42 and the drum drive motor 60 are controlled by the speed ratio.
The speed ratio is made to match the magnification by changing the number of pulses given to

7 shows the main part of the control unit of the present invention. The magnification setting buttons 62 and 80 and the print button 61 are connected to a one-chip CPU 84 with a built-in ROM via a data selector 83. On the other hand, the CPU 84 outputs a display 82 indicating that a specific magnification has been selected and a display 83 indicating the copy magnification.
81 is connected to the first means 36 for scanning the object to be copied, the second means 37 for changing the optical path length, and the third means 38 for moving the image carrier.
A clock generator 35, which is used to drive and control the pulse motors included in means 2 and 3 and to periodically sense the various switches on the control panel 34, is also connected to the CPU 84. The magnification setting buttons 62 and 80 are periodically sensed using the clock supplied from the clock generator 35, and the CPU 84 constantly updates the displays 81 and 82 based on the sensed results, and also moves the second means 37 to the optimum position. When the print button 61 is pressed, the first means 36 and the third means 38 begin operation, and copying is performed by the aforementioned operating means. To change the magnification, the user first presses the specific magnification button 62 or the magnification setting button 80. The new magnification is then displayed on the display 81. The user checks the displayed magnification. If it is different from the desired value, the user presses the button 62 or 80 again to adjust the magnification. The CPU 84 waits a while (about 2 seconds in this embodiment) after the magnification input operation is completed before using the means 36 for changing the optical path length ratio.
The second means 37 for changing the optical path length ratio is in operation and waits for a while. In other words, during this time, it is possible to change the magnification before the means for changing the optical path length ratio operates. In other words, if there are multiple inputs during the wait, the last one is considered to be the determined magnification. Also, if the magnification change button 82 or 80 is pressed while the second means 37 for changing the optical path length ratio is operating, the CPU 84 immediately stops the operation of 36, waits about 2 seconds after the magnification change button is pressed and a new magnification is set, and if the magnification change button is pressed again, the means 37 is set to the last magnification pressed at that time.
36 calculates the amount of movement from the current position to the final position, and
It is designed to move 36 along the shortest route.

Next, the operation will be explained with reference to Fig. 8. That is, when the power is turned on in st1, the process proceeds to st2 and the second means
37 operates to initialize the magnification change member to the 1:1 position. Next, in st3, it is determined whether the print button 61 has been pressed, and if "Yes", the process proceeds to st12 to start the copy operation, and if "No", it proceeds to st4 to determine whether there has been a magnification change input, and if "Yes", the process proceeds to st5 to start the timer, and if "No", the process returns to before st3.
When the timer starts, the process proceeds to st6 to determine whether a certain time has passed. If the answer is "No," the process proceeds to st13 to determine whether the magnification has been re-input, i.e., whether another specific magnification key has been pressed or whether the UP/DOWN key has been pressed continuously. If the answer is "No," the process returns to before st6.
If "Yes", proceed to st14, clear the timer and go to st5
Return to the front.

On the other hand, if it is determined that a certain time has passed since the timer started in st6, the program proceeds to st7, where the timer is cleared and the program returns to st8.
The movement amount is calculated from the current position, and the process proceeds to st9, where the movement of the magnification change member begins.

Next, in st10, it is determined whether or not a magnification change command has been input again, and if the answer is "Yes," the process proceeds to st15, where the movement of the magnification change member is stopped and the process returns to before st5. On the other hand, if it is determined in st10 that a magnification change command has not been input again, the process proceeds to st11, where it is determined whether or not the movement of the magnification change member has ended. If the answer is "No," the process returns to before st10, and if the answer is "Yes," the process returns to before st3 and waits for the print button to be pressed.

In the embodiment described above, the speed ratio between the first carriage 40 and the second carriage 41 is obtained via pulleys using the principle of a movable pulley. However, this can also be achieved by providing a dedicated motor for driving the second carriage 41 separate from the scanning motor 42 that drives the first carriage 40, and controlling the speed of each.

Furthermore, if an electromagnetic clutch is used, the operation timing of the lens block 55 and the first and second carriages 40 and 41 will be shifted, so the lens moving motor 57 and the scanning motor 42
In addition, the motors 42, 53, and 5
The motors 7 and 60 do not have to be limited to pulse motors, and any motors that can control the speed within an allowable error range may be used.
Instead of driving the first and second carriages 40 and 41 on which the document plates 5 and 6 are mounted, the document platen 2 may be moved.

The optical path length is changed by moving the second carriage 41 on which the mirrors 5 and 6 are mounted and the lens 7. However, it is possible to use multiple lenses depending on the magnification range.
Alternatively, the focal length of the lens may be changed by covering the lens 7 with a correction lens, and then the lens block 55 and the second lens block 56 are connected.
The size of the copying machine can be reduced or the range of allowable magnification changes can be widened by moving the carriage 41. Also, instead of the second carriage 41, the mirror 8 may be moved.

Furthermore, when setting the magnification, the entire fourth means 35 for setting the copy magnification, or the magnification setting button 80 and display unit 81, may be covered with an openable lid so that the user can access these areas only when necessary. In this embodiment, the magnification is set before setting the number of copies, but this is not limited to this as long as it is set before pressing the print button 61, and vice versa.

Furthermore, although a copying machine has been used as an example, it goes without saying that any image forming device can be used as long as it is capable of obtaining a copy of an object to be copied by optically scanning the object and exposing the image onto a moving image carrier via an optical system.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the spirit of the present invention.

[Effects of the Invention] As described above, the present invention has a zoom function,
In an image forming apparatus having a movable magnification change member so that the magnification can be changed by a magnification setting operation from a magnification setting means, when a second magnification is input from the magnification setting means while the magnification change member is moving to a first magnification position, the movement of the magnification change member is immediately stopped, and after this stopped state of the magnification change member continues for a predetermined time, the magnification change member starts moving to the second magnification position, thereby preventing unnecessary movement of the magnification change member and achieving the effect of enabling an image of a desired magnification to be taken quickly.

[Brief explanation of the drawings]

Fig. 1 is an explanatory diagram of the configuration of the main parts of a copying machine, Fig. 2 to Fig. 8 show one embodiment of the present invention, Fig. 2 is a schematic longitudinal front view of the copying machine, Fig. 3 is a perspective view with the document table removed, Fig. 4 is a perspective view of the optical system movement mechanism, Fig. 5 is a plan view of the lens block movement mechanism, Fig. 6 is a front view of the control panel, Fig. 7 is a block diagram of the control unit according to the present invention, and Fig. 8 is a flowchart showing the operation. A... object to be copied (document), 3... exposure lamp, 4, 5, 6, 7
......Lens, 36......Stopping means (first means), 37......Moving means (second means), 80......Optional magnification setting unit.

Claims (1)

[Claims] [Claim 1] An image forming apparatus having a magnification change function and equipped with a magnification change member that can be moved to change the magnification by a magnification setting operation from a magnification setting means, comprising: a stop means that immediately stops the movement of the magnification change member to the first position when a second magnification different from the first magnification set by the magnification setting means is set by the magnification setting means while the magnification change member is moving to a first position corresponding to the first magnification set by the magnification setting means; a timer means that measures the passage of a predetermined time; a confirmation means that confirms that a third magnification different from the second magnification has been set by the magnification setting means while the movement of the magnification change member is stopped by the stop means; and a means that moves the magnification change member to a position corresponding to the second magnification when the confirmation means does not confirm that the third magnification has been set during the time period from when the second magnification is set by the magnification setting means and the movement of the magnification change member is stopped by the stop means until the timer means measures that the predetermined time has elapsed.