JPH01182867A - Image forming device - Google Patents

Abstract

PURPOSE:To execute image formation at a high speed by accelerating a scanning means with acceleration at a minimum magnification time regardless of set magnification and controlling the acceleration in correspondence to the magnification so that a position to move to an equal speed can be same regardless of the magnification. CONSTITUTION:When equal magnification is discriminated to be set in a main processor group, a first carriage 411 is moved from a home position to a start position S2 of the equal magnification. When the first carriage 411 is moved by the acceleration at the time of the minimum reduction magnification, this start position S2 is obtained as the position where a scanning speed at the time of the equal magnification is obtained in an exposure start position S3 of an original. Thus, when the first carriage 411 is moved to the start position S2, copying operation is started and the first carriage 411 is accelerated from this start position S2. When the necessary scanning speed is achieved in the exposure start position S3 of the original, an exposure scanning is executed at the equal speed. Thus, the image formation can be executed at the high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus, such as an electronic copying machine, which exposes and scans a document to form an image corresponding to the document image.

(Prior Art) As is well known, an electronic copying machine has a function of copying an original image onto paper at the same magnification, or a function of enlarging or reducing the original image and making a copy.

(Problem to be Solved by the Invention) In an electronic copying machine, the movement speed at which the exposure scanning means exposes and scans a document is different when performing a same-size copying operation and when performing an enlargement or reduction operation. There are differences. That is, in the case of a reduced copy, the moving speed is set faster than that of a same size copy, and in the case of an enlarged copy, the moving speed is set slower than that of a same size copy. Since the exposure scanning start position of the original image is the same in all copying operations, the acceleration time required to reach the exposure scanning speed is different in the case of full-size copying and in the case of enlarged or reduced copying. .

However, in conventional electronic copying machines, the movement start position of the exposure scanning means is set at the position of the maximum reduction magnification that requires the most acceleration time, both in the case of full size copying and in the case of enlarged/reduced copying. For this reason, for example, when performing a same-size copying operation, the required scanning speed is reached before the exposure start position of the original, so the original must be moved a distance longer than necessary for exposure scanning, and the original Exposure scanning takes a long time.

This invention solves the problem that copying other than reduced copying takes more time than reduced copying, and its purpose is to shorten the time required for copying other than reduced copying compared to reduced copying. The purpose of the present invention is to provide an image forming apparatus that is possible.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an image forming apparatus capable of setting a plurality of image forming magnifications, which is accelerated by the acceleration at the minimum magnification regardless of the set magnification, A scanning means that exposes and scans the original image at a scanning speed corresponding to a set magnification, and an acceleration distance of the scanning means according to the set magnification so that the position at which the scanning speed reaches the required scanning speed is the same regardless of the magnification. and a control means for controlling.

(Function) The present invention allows the control means to accelerate the scanning means at the acceleration at the minimum magnification regardless of the set magnification, and to adjust the acceleration distance according to the magnification so that the position at which it reaches constant velocity is the same regardless of the magnification. When the magnification is larger than the minimum magnification, the approach distance of the scanning means is shortened so that image formation can be performed at high speed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 5 and 6 schematically show an image forming apparatus of the present invention, such as a copying machine. A document table (transparent glass) 2 for supporting a document is fixed to the top surface of the copying machine main body 1. The document table 2 is provided with a fixed scale 21 that serves as a reference for setting the document, and is further provided with a document cover 1 which can be opened and closed near the document table 2. and a work table 12 are provided. The original placed on the original platen 2 is processed by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7.
Exposure scanning is performed by reciprocating in the direction of arrow a along the lower surface of document table 2. in this case,
Mirror 6.7 maintains the optical path length.
It moves at a speed of /2.

The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4, is reflected by the mirror 5, 6, 7, passes through the variable magnification lens block 8, and is further reflected by the mirror. 9 and guided to the photoreceptor drum 10, so that an image of the document is formed on the surface of the photoreceptor drum 10.

The photosensitive drum 10 is rotated in the direction of arrow C in the figure, and first, the surface thereof is charged by the charging device 11. Thereafter, the image is exposed to slit light to form an electrostatic latent image on the surface. This electrostatic latent image is made visible by applying toner by the developing device 12.

On the other hand, the paper (transfer material) P is taken out one by one from the selected upper paper feed cassette 13 or lower paper feed cassette 14 by the delivery roller 15 or 16, and the taken out paper is taken out from the paper guide path 17 or 18 and is guided to a pair of registration rollers 19, and guided to a transfer section by this pair of registration rollers 19. Here, the paper feed cassettes 13 and 14 are removably provided at the lower right end of the main body 1, and one of them can be selected from an operation panel to be described later.

The cassette size of each of the paper feed cassettes 13 and 14 is detected by a cassette size detection switch 601 and 602, respectively. The cassette size detection switches 601 and 602 are composed of a plurality of microswitches that are turned on and off in accordance with the insertion of cassettes of different sizes.

The paper P sent to the transfer section is brought into close contact with the surface of the photoreceptor drum 10 at the transfer charger 20, and
The toner image on the photoreceptor drum 10 is transferred by the action of 0. The transferred paper P is electrostatically peeled off from the photosensitive drum 10 by the action of a peeling charger 21, and is sent by a conveyor belt 22 to a fixing roller 23 as a fixing device provided at the end thereof. The transferred image is fixed by passing through this, and the fixed paper P is discharged to a tray 25 outside the main body 1 by a pair of paper discharge rollers 24 . Further, the photoreceptor drum 10 after the transfer is transferred to a charger 2 for removing static electricity.
6, residual toner on the surface is removed by a cleaner 27, and afterimages are erased by a static elimination lamp 28, so that the initial state is restored. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

FIG. 7 shows the operation panel 30 provided on the main body 1. 301 is a copy key for instructing the start of copying; 302
is a numeric keypad for setting the number of copies, etc.; 303 is a display unit that displays the operating status of each section and paper jams; 304 is a cassette selection key for selecting the upper and lower paper feed cassettes 13 and 14; 305 is a selected key. A cassette display section for displaying the cassette, 306 a magnification setting key for setting the enlargement and reduction magnification of copies in a predetermined relationship, 307 a zoom key for steplessly setting the enlargement and reduction magnification, and 30B for displaying the set magnification. A display section 309 is a density setting section for setting copy density.

FIG. 8 shows a drive mechanism for reciprocating the optical system. That is, the mirror 5 and the exposure lamp 4
is the first carriage 41. The mirrors 6.7 are respectively supported by second carriages 412, and these first and second carriages 4111412 are supported by guide rails 421.42.
2 and can freely move in parallel in the direction of arrow a. Further, the four-phase pulse motor 33 drives a pulley 43. This pulley 43 and idle pulley 4
An endless belt 45 is stretched between the first carriage 41 . One end is fixed.

On the other hand, two pulleys 47.47 are rotatably provided in the guide section 46 of the second carriage 412 that supports the mirror 6.7, spaced apart in the axial direction of the rail 422. A wire 48 is strung around.

One end of this wire 48 is fixed to a fixed part 49, and the other end is fixed to the fixed part 49 via a coil spring 50. Further, one end of a first carriage 411 is fixed to a midway portion of the wire 48. Therefore, by rotating the pulse motor 33, the belt 45 rotates and the first carriage 41□ is moved, and the second carriage 412 is also moved accordingly. At this time, since the pulleys 47.47 serve as movable pulleys, the first carriage 41. In contrast, the second carriage 412 is moved in the same direction at 1/2 the speed. Note that the moving directions of the first and second carriages 411 and 412 are controlled by switching the rotation direction of the pulse motor 33.

FIG. 1 shows the overall control circuit.

For example, a main processor group 71 constituted by a one-chip microcomputer detects human power from an input device 75 such as the operation panel 30 and various switches and sensors, such as the cassette size detection switch 601, 60□, and High voltage transformer 76 that drives
, the static elimination lamp 28, the blade solenoid 27a of the cleaner 27, the heater 23a of the fixing roller pair 23
, the exposure lamp 4, and each of the motors 32 to 40, etc., to perform the above-described copying operation.

Among the above motors 32 to 40, motor 35.37.40
and developing device 121;: A toner motor 77 that supplies toner is controlled by the main processor group 71 via a motor driver 78, and the motors 32 to 34 are controlled by the first sub processor group 72 via a pulse motor driver 79. The motors 36, 39, 38 are controlled by the second sub-processor W73 via a pulse motor driver 80.

Here, 32 is a lens motor, which is a motor for moving the position of the lens block 8 for changing the magnification. A scanning motor 33 is a motor for moving the exposure lamp 4, the mirror 5, and the mirror 6.7 for scanning the original. 34 is a shutter motor, which is a motor for moving a shutter (not shown) for adjusting the charging width of the photosensitive drum 1o by the charger 11 during zooming. A developing motor 35 is a motor for driving the developing roller of the developing device 12 and the like. 36 is a drum motor;
This is a motor for driving the photosensitive drum 1o.

Reference numeral 37 denotes a fixing motor, which is a motor for driving the paper conveyance path 22, the pair of fixing rollers 23, and the pair of paper discharge rollers 24.

38 is a paper feed motor, and the feed roller 15, 16
This is a motor for driving. A paper feeding motor 39 is a motor for driving the registration roller pair 19. A fan motor 40 is a motor for driving the cooling fan 29.

Further, the exposure lamp 4 is controlled by the main processor group 71 via the lamp regulator 81, and the heater 23a is controlled by the main processor group 71 via the heater control section 82. Then, commands to drive and stop each motor are sent from the main processor group 71 to the first and second sub-processor groups 72.73.
3, a status signal indicating the drive/stop state of each motor is sent to the main processor group 71. Further, position information from a position sensor 83 that detects the initial position of each of the motors 31 to 34 is input to the first sub-processor group 72. These first and second sub-processor groups 72.73
, for example, includes a microcomputer and a programmable φ interval timer that counts reference clock pulses according to a set value supplied from the microcomputer and controls the phase switching interval time of the pulse motor.

° In the above configuration, with reference to FIGS. 2 to 4,
The operations of the main processor group 71 and the first carriage 411 during image formation will be described. still,
In the standby state, the first carriage 411 uses, for example, the fixed scale 21 and the scale 53 (shown in FIG. 9) provided on the first carriage 411 to set a copy range corresponding to the currently set copy magnification and paper size. It is assumed that the robot is stopped at the position shown (referred to as the home position).

In the main processor group 71, when the copy key 301 is operated, in step ST1' shown in FIG.
It is determined whether the set copy magnification is equal to or not. As a result, if a reduction or enlargement ratio other than the same amount is set, a normal reduction or enlargement copying operation is performed in step ST2. For example, if the minimum reduction magnification is set, the first carriage 41. However, from the home position to the starting position S1 shown in FIG.
, and is accelerated from this start position S1, and when the scanning speed (original exposure start position 83) is reached, the original is exposed and scanned at a constant speed. When the reduction copying operation for the set number of original images is completed in this way, the first carriage 41. is returned to the home position and placed in a standby state.

Further, if it is determined in step ST1 that the same size is set, in step ST3,
The first carriage 411 is moved from the home position to the same-size start position S2 shown in FIG.

When the first carriage 411 is moved with an acceleration similar to the acceleration at the time of the minimum reduction magnification, the start position S2 is at the exposure start position S3 of the document.
This is the position that corresponds to the scanning speed at the same magnification. Here, the distance between the start positions S1 and 82 is, for example, 3. 93 (o
rIIl).

In this way, the first carriage 41. is moved to the start position S2, the copying operation is started in step ST4, and the first carriage 41. is this starting position S2
The scanning speed is accelerated from 1 to 3, and reaches a required scanning speed at the exposure start position S3 of the original, and the original is exposed and scanned from this position S3 at a constant speed.

The image forming process accompanying exposure scanning of the original is similar to the operation described above.

In this way, when exposure scanning of the original is performed, the first carriage 411 is returned to the start position S2 at a speed faster than the exposure speed, and if there are remaining sheets, the first carriage 411 is returned from the start position S2. is moved,
A similar copying operation is performed (steps S75-4).

When all remaining sheets have been copied, the first carriage 41. is moved to the home position mentioned above,
It is placed on standby.

FIG. 4 shows one reciprocation of the first carriage 411 at the same magnification, where the solid line is for this embodiment and the dotted line is for the conventional one.

As is clear from the figure, in this embodiment, the run-up distance of the first carriage 411 is shortened when the magnification is the same, so the time required for the first carriage 411 to make one round trip can be shortened compared to the conventional case. It is something. Therefore, it is possible to shorten the time required to copy -a sheet.

In FIG. 4, the required time for each part is as follows.

Acceleration time TI -29.6 (ms) Scanning time T2 - 1939.0 (ms) Deceleration time T3 -
29.6 (Ills) Switching time T4- 54.
6 (ms) Acceleration time T5- 96.8 (ms) Return time T6- 699 (ms) Deceleration time T7-
96.8 (ms) switching time T8 = 54.6
(ms) Therefore, the time required for one copy is 300 ms.
0 (ms), which corresponds to 20 A4 size sheets/minute.

On the other hand, when the start position is not moved as in the conventional case and the start position is accelerated from the minimum reduction magnification, the distance 3.93 (■) between the start position S1' and the first carriage 41. This will be added to both round trips. Therefore, if the scanning speed is -121 (10111/S) and the return speed is -292,86 (IIl dew/s), then the time is (3,93/121 +3.93/292.86) xlO3 -45,9 ( as), and 45. The time increases by 9 (ms) minutes. Therefore, the time required for one copy is 3000+45.9-3045.9 (ass), which corresponds to 19.7 A4 size sheets/minute.

In this way, by moving the start position, 0.
The copying speed can be increased by 3 sheets/min, and when the number of copies is large, a remarkable effect can be obtained.

In the above embodiment, the first carriage 411 is used only when the magnification is the same.
Although the start position of the first carriage 411 is changed, the time required for enlarged copying can be shortened by changing the start position of the first carriage 411 in the same way when the enlargement magnification is set.

Furthermore, the home position of the first carriage 411 is set to a position indicating the copying range according to the set copying magnification;
The position is not limited to this, and may be, for example, the starting position of the minimum reduction magnification.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, the control means accelerates the scanning means by the acceleration at the minimum magnification regardless of the set magnification, and the position at which the speed changes to a constant speed remains constant regardless of the magnification. By controlling the acceleration distance according to the magnification so that the distance is the same, it is possible to provide an image forming apparatus that can form images at high speed by shortening the run-up distance of the scanning means when the magnification is larger than the minimum magnification. .

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a configuration diagram showing a control system, FIGS. 2 to 4 are diagrams shown to explain the operation, and FIGS. 5 and 6. 5 shows a perspective view of the image forming apparatus, FIG. 6 shows a side sectional view, FIG. 7 shows a plan view showing the configuration of the operation panel, and FIG. 8 shows the drive mechanism of the optical system. FIG. 2 is a schematic perspective view. 1... Copying machine main body, 30... Operation panel, 306.
・・Magnification setting key, 411 ・・1st carriage, 71
...Main processor group. Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In an image forming apparatus capable of setting a plurality of image formation magnifications, the original image is accelerated by the acceleration at the minimum magnification regardless of the set magnification, and the original image is formed at a scanning speed according to the set magnification. and a control means for controlling the acceleration distance of the scanning means in accordance with a set magnification so that the position at which the scanning speed reaches the required scanning speed is the same regardless of the magnification. image forming apparatus.