JPH07168506A - Image forming device - Google Patents

Abstract

PURPOSE:To shorten the first print time by judging whether or not a rotary polygon mirror is capable of image forming before a transfer-material tip holding position reaches, and controlling the transfer of the transfer material to a transfer drum. CONSTITUTION:A CPU 101 is provided with a ROM for storing a control program corresponding to an image formation sequence including a control procedure and a RAM for keeping control information, etc., and monitors the rotation state of the rotary polygon mirror 13 via an input port. The rotating speed of the rotary polygon mirror 13 is also detected by a detecting mechanism such as a photo-encoder, and the information is given to the CPU 101. At the time when the position detecting means detects a prescribed position, the CPU 101 decides whether image formation is possible or not, based on the result of the detection by the rotating speed detecting means and controls the idle rotation of the transfer drum 10 based on the result of the decision. Therefore, the rise of the rotary polygon mirror 13 occurs at the same time as the movement of the transfer drum 10 from the transfer material tip holding position to a transfer material hold starting position, and the first print time is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image forming apparatus capable of forming a color image on a latent electrostatic image bearing member by using a developing device for a plurality of colors. After uniformly charging, the laser beam is scanned by the rotating polygon mirror to perform image exposure based on the image information converted into an electrical signal to form an electrostatic latent image, and the image is visualized with toner. The present invention relates to an image forming apparatus in which a transfer material wound in advance on a transfer drum is transferred, fixed, and then discharged as a printed matter to the outside of the apparatus.

[0002]

2. Description of the Related Art In a color image forming apparatus of this type, a process of transferring a recording image formed on an image bearing member by charging, exposing and developing onto a recording paper is repeated a plurality of times to form a plurality of colors on the recording paper. There is a method of forming a superimposed image to obtain a color image. An image forming apparatus of this type is disclosed in Japanese Patent Laid-Open No.
It has been put to practical use with the configuration described in Japanese Patent No. 50935.

FIG. 5 is a sectional view of a color image forming apparatus of this type, and FIG. 6 is an enlarged sectional view for explaining the structure around the developing device shown in FIG.

As shown in these figures, the photosensitive drum 1, the corona charger 2, the roller charger 3, which are image bearing members in the entire apparatus, and the right side of the photosensitive drum 1 are
A plurality of developing devices 4a, 4b, 4c, 4d are carried by a rotatable support, and the developing opening surfaces 5a of the developing devices 4a, 4b, 4c, 4d are arranged on the same cylinder centered on the support rotation axis. , 5
b, 5c and 5d are set. Also, the developing device 4
As shown in FIG. 6, yellow toner, magenta toner, cyan toner, and black toner are contained in a, 4b, 4c, and 4d, respectively, and further, coating rollers 6a, 6b, and
6c, 6d and toner regulating members 7a, 7b, 7c, 7d, and the developing rollers 8a, 8b, 8b, 8c, 8d on the toner applying rollers 6a, 6b, 6c, 6d as the developing rollers 8a, 8b, 8c, 8d rotate. Apply toner on 8c and 8d,
Further, the toner regulating members 7a, 7b, 7c, 7d give necessary tribo to the toner. The material of the regulating member is preferably nylon or the like when the toner has a negative polarity, and silicone rubber or the like when the toner is positively charged, and is preferably a material that is charged opposite to the polarity of the toner.

The peripheral speed of the photosensitive drum 1 is 1.0 to 2.
It is preferable to select the peripheral speed in the range of 0 times.

Further, the developing devices 4a, 4b, 4c and 4d attached to the support shaft 9 are provided with developing opening surfaces 5a, 5b, 5d of the developing devices 4a, 4b, 4c and 4d, as shown in FIG.
5c and 5d are always driven so as to face the surface of the photosensitive drum 1. One means of driving method is described in detail in Japanese Patent Laid-Open No. 50-93437.

On the left side, there is arranged a transfer drum 10 which carries a transfer material (not shown) and has a function of transferring an image on the photosensitive drum 1 to the transfer material (not shown). With the above configuration, the photosensitive drum 1 is driven in the direction of the arrow shown by the driving means (not shown) at a peripheral speed of 100 mm / sec. The photosensitive drum 1 has a diameter of 40 m.
Although a photoconductor made of an organic photoconductor (OPC) is applied to the outer peripheral surface of an aluminum cylinder of m, the OPC may be A-Si, CdS, Se or the like.

Next, a laser diode 11, which constitutes an exposure device, a rotary polygon mirror 13, which is driven to rotate by a high-speed motor 12, a lens 14, and a folding mirror 15, are arranged above the inside of the main body of the apparatus, and the above-mentioned roller is used. (Charger) 3 has a DC voltage of 700V and an AC frequency of 700H.
An alternating voltage of Vpp (peak-to-peak) 1500v is superimposed on z and uniformly charged to about 700V. When a signal according to a yellow image pattern is input to the laser diode 11, the photosensitive drum 1 is irradiated through the optical path 16, and the photosensitive drum 1 is irradiated with light at a voltage of about 100V.
become.

When the photosensitive drum 1 further advances in the arrow direction, it is visualized by the developing devices 4a, 4b, 4c and 4d.

Next, the transfer process will be described in detail.

The transfer drum 10 has a diameter of 156 m.
The elastic layer 20 having a thickness of 2 mm is wound around the metal cylinder 19 of m, and the PVDF 21 having a thickness of 100 μm is further wound around the upper layer. The elastic layer 20 is urethane foam made by Inoac. The transfer material fed from the transfer material cassette 17 by the pickup roller 18 is
It is held by the gripper 22, and then electrostatically attracted to the transfer drum 10 by the attracting roller 23 to which a voltage is applied.

The toner image on the photosensitive drum 1 is transferred onto a transfer material (not shown) attracted to the transfer drum 10 by a voltage applied to the transfer drum 10 from a power source (not shown). By performing the above steps for magenta, cyan, and black, toner images of a plurality of colors are formed on the transfer material. The transfer material is peeled from the transfer drum 10 by the separating claw 24, and the transfer material is melted and fixed by a conventionally known heating and pressure fixing device 25 to obtain a color image.

Further, the transfer residual toner on the photosensitive drum 1 is a known fur brush, a cleaning device 26 of blade means.
To be cleaned by.

Further, the toner on the transfer drum 10 is also preferably cleaned by a transfer drum cleaning device 27 such as a fur brush or a web, if necessary. here,
The transfer drum 10 is in contact with the image carrier with a nip at the time of transfer, but it is desirable to keep it away from the image carrier in consideration of deformation and the like when stopped.

Therefore, since the gripper is not in contact with the image carrier, the position where this part faces the image carrier is set as the home position, and the gripper is always stopped at this position.

[0016]

In recent years, image forming apparatuses such as laser printers are strongly demanded to have high image quality, and in terms of resolution, they are advancing toward 600 dpi and 800 dpi. Furthermore, from the viewpoint of environmental protection, we do not want to waste even one sheet of paper. Such a request is the same for the color image forming apparatus as described above.

The inventors of the present invention have conducted extensive studies to meet the above demands, but the following problems have occurred in the color image forming apparatus as described above.

First, the start-up of the image forming apparatus will be described in detail. When a print signal is input, the rotary polygon mirror 13 is rotated, and at the same time, the transfer drum 10 and the photosensitive drum 1 are rotated. Then, the gripper 2 of the transfer drum 10
2 starts from the home position, and when it reaches a predetermined position, it holds the transfer material sent in synchronization with this.

When the process further proceeds, and when the front end of the transfer material reaches the transfer position (the contact portion between the photosensitive drum 1 and the transfer drum 10), the toner image on the photosensitive drum which is formed in synchronization in advance is transferred. . At this time, if it takes longer than usual to rise the rotary polygon mirror 13, the timing of forming an image to be formed on the photosensitive drum is delayed.

If the image-formable time is delayed as described above, it becomes impossible to form an image in accordance with the position of the leading edge of the transfer material. In this case, in the mono-color laser printer, no problem occurred if the transfer material was allowed to wait in the middle of the conveying section until the rotary polygon mirror 13 stood up. In the color image forming apparatus, however, the transfer material was transferred. Gripper 2 on drum 10
Since it must be fixed to 2, it cannot be made to stand by on the rotating transfer drum 10, and if the transfer drum is tried to rotate once again while holding the transfer material, the transfer material is lowered due to a decrease in electrostatic attraction force. And the transfer drum may be separated from each other, which may cause a jam. However,
It is necessary to discharge the transfer material once outside the main body, and the transfer material is wasted.

Therefore, in order to avoid this, the rotary polygon mirror 1
It is conceivable that only No. 3 is started up first, and after a predetermined steady rotation, the transfer drum, the photosensitive drum, etc. are started to rotate.

However, this method has a number of problems such as a very long first print time.

The present invention has been made to solve the above-mentioned problems, and the rotary polygon mirror is provided before the transfer material tip holding position reaches the transfer material holding start position at the start of the image forming operation. An object of the present invention is to provide an image forming apparatus capable of reducing the first print time by determining whether or not an image can be formed and controlling transfer of a transfer material onto a transfer drum.

[0024]

An image forming apparatus according to the present invention comprises a position detecting means for detecting a reference position on a transfer drum passing a predetermined position, and a rotation detecting means for detecting the number of rotations of the rotary polygon mirror. The number detecting means, a starting means for simultaneously starting the rotation of the rotary polygon mirror and the rotation for moving the holding position for holding the transfer material on the transfer drum to a predetermined holding start position, and the position detecting means When a predetermined position is detected, a determination unit that determines whether image formation is possible based on the detection result of the rotation speed detection unit, and a control that controls the idle rotation of the transfer drum based on the determination result of this determination unit And means are provided.

[0025]

In the present invention, when the determination means detects the predetermined position by the position detection means, it is determined whether or not an image can be formed based on the detection result of the rotation speed detection means, and the control is performed based on the determination result. Since the means controls the idle rotation of the transfer drum, the start of the rotary polygon mirror and the movement of the transfer material tip holding position of the transfer drum to the transfer material holding start position are performed in parallel to shorten the first print time. It becomes possible.

[0026]

【Example】

[First Embodiment] FIG. 1 is a schematic view for explaining a main structure of an image forming apparatus according to a first embodiment of the present invention. The same parts as those in FIG. 5 are designated by the same reference numerals.

In the figure, reference numeral 102 designates a registration roller, and the transfer material 103 is properly gripped at the grip position A.
It is provided to measure the timing of sending to 2 and make it stand by. In addition, a sensor (not shown) for detecting the arrival timing of the gripper 22 is provided, or the transfer drum 10
The passage of the position B (the position that determines the judgment reference timing) is detected by the timing processing (internal timer processing) after the reference position of (1) has passed.

Reference numeral 101 denotes a CPU section for controlling the entire apparatus,
ROM storing a control program corresponding to an image forming sequence including a control procedure shown in a flowchart described later
Also, a RAM for holding control information and the like are provided, and the rotation state of the rotary polygon mirror 13 is monitored via an input port (not shown). The rotation speed of the rotary polygon mirror 13 is also detected by a detection mechanism such as a photo encoder, and the CPU
It is assumed that the unit 101 has been notified.

In the image forming apparatus thus constructed, when the CPU section 101 detects the predetermined position by the position detecting means, it is judged whether or not an image can be formed based on the detection result of the rotation speed detecting means. Since the idle rotation of the transfer drum 10 is controlled based on the determination result, the startup of the rotary polygon mirror 13 and the movement of the transfer material tip holding position of the transfer drum 10 to the transfer material holding start position are performed in parallel, It is possible to shorten the first print time.

In this embodiment, the process speed V
p = 100 (mm / sec), resolution x = 300 dp
i, the number of surfaces of the rotating polygon mirror 13 is n = 6. Here, the rotation speed Y of the rotary polygon mirror is Y = 11811 (rp
m).

Next, the image forming sequence processing operation in the image forming apparatus according to the present invention will be described with reference to the flow chart shown in FIG.

FIG. 2 is a flowchart showing an example of a first image forming sequence processing procedure in the image forming apparatus according to the present invention. Note that (1) to (6) indicate each step. First, when a print signal comes in, the rotary polygon mirror 1
When the rotation of No. 3 is started, at the same time, a signal for starting the rotation of the transfer drum 10 and the photosensitive drum 1 is output to each rotary drive system via the driver to start the rotation (1).

Next, the transfer material 103 is fed by the pickup roller 18, and then the registration roller 102.
To wait. Then, when the gripper 22 of the transfer drum 10 starts from the home position and reaches the judgment position B, it is judged whether or not the rotary polygon mirror 13 has reached the predetermined rotation speed (2), and the predetermined rotation speed has been reached. Then, the registration roller 102 is rotated (4), and the transfer material 1
03 is conveyed to the grip position A and gripped (5). After this point, the normal image operation is performed (6), and when the image formation based on the set mode is completed, the image forming process is completed.

In this embodiment, the rotary polygon mirror 13 is
A certain number of rotations from the stationary state, for example 11811 (rp
It takes about 2 (sec) to reach m). The time from when the gripper 22 of the transfer drum 10 starts to rotate from the home position (transfer position) to when it reaches the determination position B is about 2.5 (sec).

Therefore, it is possible to print about 2 (sec) earlier than when the transfer drum 10 and the photosensitive drum 1 are rotated after the rotary polygon mirror 13 is raised. When the gripper 22 of the transfer drum 10 reaches the determination position B, and the rotary polygon mirror 13 has not reached the predetermined number of rotations, the transfer drum 10 is rotated once more (3), and the gripper 22 again determines. When it comes to the position B, a judgment is made.

According to this embodiment, at the start of the image forming operation, it is determined whether or not the rotary polygon mirror can form an image before the holding position of the transfer material reaches the holding position of the transfer material. In this case, the start-up of the rotary polygon mirror 13 and the movement of the transfer material tip holding position of the transfer drum 10 to the transfer material holding start position are processed in parallel, so that an image forming apparatus having a short first print time is provided. It has become possible. [Second Embodiment] FIG. 3 is a flowchart showing an example of a second image forming sequence processing procedure in the image forming apparatus according to the present invention. Note that (1) to (7) indicate each step. In this embodiment, the process speed Vp = 1
00 (mm / sec), resolution x = 600 dpi, and the number of surfaces of the rotating polygon mirror 13 is n = 6. Here, the rotation speed Y of the rotary polygon mirror is Y = 23622 (rpm).

When a print signal is input, first, the rotary polygon mirror 13 is rotated based on the same control instruction as above (1), and after 3 seconds, the transfer drum 10 and the photosensitive drum 1 are rotated (2). . Further, the transfer material 103 is fed by the pickup roller 18 and then made to stand by by the registration roller 102. And the transfer drum 10
When the gripper 22 starts from the home position and reaches the judgment position B, it is judged whether or not the rotary polygon mirror 13 has reached a predetermined rotation speed (3), and if the predetermined rotation speed is reached, the registration is performed. Rotate the roller 102 (5),
The transfer material 103 is conveyed to the grip position A and gripped (6). After this point, the normal image forming apparatus is performed (7), and when the image formation based on the set mode is completed, the image forming process is completed.

In this embodiment, the rotary polygon mirror 13 is
It takes about 5 (sec) to reach 23622 (rpm) from the stationary state. Further, the time required for the gripper portion of the transfer drum 10 to start to rotate from the home position (transfer position) and reach the judgment position B is about 2.5.
(Sec).

Therefore, an image can be formed by the first rotation of the transfer drum 10, and it is about 2 (se) more than when the transfer drum and the photosensitive drum are rotated after the rotary polygon mirror is raised.
It became possible to print c) sooner.

When the gripper 22 of the transfer drum 10 has reached the judgment position B and the rotary polygon mirror 13 has not reached the predetermined number of rotations, the transfer drum 10 is rotated once again (4), and the gripper is rotated again. When 22 reaches the determination position B, the same determination as above is performed.

According to the present embodiment, at the start of the image forming operation, the CPU section 101 determines whether or not the rotary polygon mirror can form an image before the holding position of the transfer material reaches the holding position of the transfer material. Is performed, and the start of the rotary polygon mirror 13 and the movement of the transfer material front end holding position of the transfer drum 10 to the transfer material holding start position are processed in parallel based on the result of the judgment, so that a high quality color image is formed. As for the apparatus, it is possible to provide an image forming apparatus having a short first print time. [Third Embodiment] FIG. 4 is a flowchart showing an example of a third image forming sequence processing procedure in the image forming apparatus according to the present invention. Note that (1) to (9) indicate each step. In this embodiment, the process speed Vp = 1
00 (mm / sec), resolution x = 600 dpi, and the number of surfaces of the rotating polygon mirror 13 is n = 6. Here, the rotation speed Y of the rotary polygon mirror is Y = 23622 (rpm).

When a print signal is input, the rotary polygon mirror 13 is first rotated (1). This rotation situation is CPU
Although the unit 101 monitors the rise time, in the present embodiment, the rise time is predicted from the rise situation. For example, 100 (rp
m) to 1000 (rpm), and the time T1 to reach 23622 (rpm) from the measured time
Guess (2). When the arrival time becomes smaller than the time T2 when the gripper 22 of the transfer drum 10 starts rotating from the home position (transfer position) and reaches the determination position B (3), the transfer drum 10 and the photosensitive drum 1 Rotate (4). Further, the transfer material 103 is fed by the pickup roller 18 and then made to stand by by the registration roller 102.
0 gripper 22 starts from home position,
When it comes to the determination position B, the CPU unit 101 determines whether or not the rotary polygon mirror 13 has reached a predetermined rotation speed (5),
If the predetermined number of rotations has been reached, the registration roller 102 is rotated (7), the transfer material 103 is conveyed to the grip position A, and gripped (8). Then, a normal image forming operation is performed (9), and when the image formation based on the set mode is completed, the image forming process is completed.

On the other hand, in step (5), when the gripper 22 of the transfer drum 10 reaches the judgment position B, if the rotary polygon mirror 13 has not reached the predetermined rotation speed, the CPU portion 101
When the judgment is made, the transfer drum 10 is rotated once more (6), and when the gripper 22 reaches the judgment position B again, the judgment is made.

By doing so, it is possible to absorb individual differences in the rising time of the rotary polygon mirror and variations in the rising time due to temperature, and it is possible to always print in the shortest time.

[0045]

As described above, according to the present invention,
When the position detecting means detects the predetermined position, the judging means judges whether or not the image can be formed based on the detection result of the rotation speed detecting means, and the control means controls the idle rotation of the transfer drum based on the judgment result. Therefore, the start of the rotary polygon mirror and the movement of the transfer material tip holding position of the transfer drum to the transfer material holding start position are performed in parallel, and the first print time can be shortened.

Therefore, there is an effect that the first print time in the image forming apparatus capable of forming the high quality color image can be greatly shortened.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a main part of an image forming apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a first image forming sequence processing procedure in the image forming apparatus according to the present invention.

FIG. 3 is a flowchart showing an example of a second image forming sequence processing procedure in the image forming apparatus according to the present invention.

FIG. 4 is a flowchart showing an example of a third image forming sequence processing procedure in the image forming apparatus according to the present invention.

FIG. 5 is a sectional view of a color image forming apparatus of this type.

FIG. 6 is an enlarged cross-sectional view illustrating a configuration around the developing device illustrated in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 10 Transfer drum 12 High-speed motor 13 Rotating polygonal mirror 101 CPU section 102 Registration roller

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Naoki Enomoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Toshihiko Ochiai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (1)

[Claims] 1. An optical system for deflecting a laser beam modulated based on image information by a rotating polygon mirror to form an image on a photoconductor, and a transfer drum for winding a transfer material. An image forming apparatus for forming an image by transferring the image developed on the photoconductor to the transferred transfer material; position detecting means for detecting that a reference position on the transfer drum passes a predetermined position; A rotation speed detecting means for detecting the rotation speed of the rotary polygon mirror, a start-up rotation of the rotary polygon mirror, and a rotation for moving the holding position for holding the transfer material on the transfer drum to a predetermined holding start position are simultaneously started. A starting unit, a determination unit that determines whether image formation is possible based on the detection result of the rotation speed detection unit at the time when the position detection unit detects the predetermined position, and a determination result based on the determination result of the determination unit. An image forming apparatus comprising: a control unit that controls idle rotation of the transfer drum.