JPH09244316A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the copying speed by carrying a transfer material to a transfer area at a higher speed than the process speed from the timing to start the carriage of a recording paper to the timing to start the forming of the electrostatic latent image in a case of a to first transfer material. SOLUTION: In a case of a first transfer material in forming one or a plurality of transfer materials 44 to be carried to a transfer area to form a series of images, the transfer materials 44 are carried toward the transfer area at a higher speed than the process speed from the timing to start carriage to the timing to start forming the electrostatic latent image. For example, when the required number of copies is one, the signal to drive a drive motor 12 at a speed twice the process speed is received by a main drive motor driver from a controller 60, and the main drive motor 12 is driven at the doubled speed. Thus, the transfer materials 44 are carried from a tray 46 to a resist roller 50 at a speed twice as the process speed, and the copying speed is in creased by that amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic method has been widely used. This electrophotographic image forming apparatus, for example, scans a document illumination lamp along a document and rotates a drum-shaped image carrier (photoconductor) at a predetermined process speed while charging the photoconductor. Is uniformly charged, the light carrying the information of the image recorded on the original is applied to the photoconductor to form an electrostatic latent image on the photoconductor, and the electrostatic latent image is developed using a developer. It is a device for forming a developed image by transferring the developed image to a sheet (transfer material) conveyed to a transfer area to obtain a print image (copy image).

In such an image forming apparatus, the process speed for rotating the photosensitive member is determined based on the characteristics (photosensitivity and charging ability) of the photosensitive member. Further, the scanning speed of the document illumination lamp, the conveying speed of the paper, etc. are determined based on this process speed, and the copying speed (for example, the number of copies per minute) is calculated from these speeds. Conventional techniques for increasing the copying speed include
A technique has been proposed in which a plurality of sheets of paper are continuously conveyed to form a series of images, and the distance between the sheets is narrowed.

The following two basic techniques are known as techniques for reducing the distance between sheets in this way.

The first technique is to set the start-up time until the optical motor for scanning the optical system having the above-mentioned document illumination lamp reaches a constant rotation speed and the stop time until the optical motor stops from the constant rotation speed. It is a technique of shortening. The second technique is a technique for shortening the return time for the optical system that has finished scanning the document to return to the original start position. As described above, in order to shorten the start-up time and the return time of the optical motor in order to narrow the space between the sheets, an expensive optical motor with high torque is required, and the cost of the entire apparatus increases accordingly.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus which has a higher copying speed than ever before.

[0007]

A first image forming apparatus of the present invention for achieving the above object forms an electrostatic latent image on an image bearing member rotating at a predetermined process speed and uses a developer. In an image forming apparatus that develops the electrostatic latent image on the lever and transfers the developed image to a transfer material in a predetermined transfer area, (1) a transfer device that transfers the transfer material to the transfer area, and (2) a transfer device that transfers the transfer material to the transfer area this time. When the transfer material being conveyed is the first transfer material of a series of image formation of one sheet or a plurality of sheets, from the timing of starting the conveyance of the recording sheet to the timing of starting the formation of the electrostatic latent image. A first control device for controlling the transfer device so as to transfer the transfer material toward the transfer area at a speed higher than the process speed is provided.

The second image forming apparatus of the present invention for achieving the above object forms an electrostatic latent image on an image carrier which rotates at a predetermined process speed, and uses a developer to form the electrostatic latent image. In an image forming apparatus that develops a latent image and transfers the developed image to a transfer material in a predetermined transfer area, (3) a discharge device that discharges the transfer material onto which the developed image has been transferred (4) this time is conveyed to the transfer area In the case where the number of recording materials is 1, the transfer material passes from the timing when the transfer material passes through the transfer area to the timing when the transfer material is discharged.
A second control device is provided for controlling the discharging device so that the transfer material is discharged at a speed higher than the process speed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of an image forming apparatus.

The image forming apparatus 10 includes a main drive motor 1
A photosensitive drum (which is an example of the image bearing member according to the invention) 20 that rotates in the direction of arrow A by 2 is provided. The photoconductor drum 20 includes a conductive substrate (not shown) made of aluminum or the like, and a CGL laminated on the conductive substrate.
(Charge generation layer) and a photoconductor layer (not shown) including a CTL (charge transport layer), and based on the characteristics (photosensitivity, charging ability, etc.) of the photoconductor layer, The rotation speed (process speed) is determined. Photoconductor drum 2
The primary charger 22 is disposed so as to face 0, and the corona discharge from the primary charger 22 causes the photoconductor drum 20 to move.
Are uniformly charged.

The image forming apparatus 10 also includes a document table 26 on which the document 24 is placed, and the document 24 placed on the document table 26 is illuminated by a document illumination lamp 28. The original illumination lamp 28 includes various mirrors 30a,
30b, 30c, 30d, 30e, 30f and the lens 3
The optical scanning unit 30 is a part of the optical scanning unit 30, and a part of the optical scanning unit 30 reciprocates in the direction of arrow B by the optical drive motor 32 (see FIG. 2) according to the rotation speed of the photoconductor drum 20. . Optical scanning unit 30
An optical scanning unit position sensor 31 for detecting whether or not the optical scanning unit 30 is located at the scanning start position is arranged near the position. Light is reflected from the document 24 irradiated with the light from the document illumination lamp 28, and the document exposure 34 (light carrying image information), which is the reflected light, irradiates the photoconductor drum 20, and thereby the photoconductor drum 20 is illuminated. An electrostatic latent image is formed.

A developing sleeve 36 for developing an electrostatic latent image is provided on the downstream side in the rotation direction of the photoconductor drum 20 with respect to the position where the photoconductor drum 20 is irradiated with the document exposure 34. The developing sleeve 36 is used for the main drive motor 12
Rotates in the direction of arrow C. When the electrostatic latent image formed on the photosensitive drum 20 reaches a position facing the developing sleeve 36, toner is supplied from the developing sleeve 36 to the electrostatic latent image, and the toner image (developed image) is formed on the photosensitive drum 20. Is formed.

A transfer area 38 where the developed image is transferred to a transfer sheet.
A transfer device 40 is arranged in the. In addition, the transfer area 38
A cleaning device 42 is arranged on the downstream side of the photosensitive drum in the rotation direction.
As a result, the toner remaining on the photoconductor drum 20 after the transfer is scraped off.

The transfer paper 44 is housed in a tray 46, and is a paper feed roller (which is an example of a carrying device according to the invention) 48 which is rotated in the direction of arrow D by the main drive motor 12.
Is conveyed toward the transfer area 38 by the registration roller 50.
Sandwiched between. The registration roller 50 is also rotated in the arrow E direction by the main drive motor 12. A pre-registration sensor 62 is arranged slightly upstream of the registration rollers 50 in the transfer paper conveyance direction. The pre-registration sensor 62 detects the presence or absence of the leading edge of the transfer paper 44. The transfer paper conveyed to the registration rollers 50 is conveyed to the transfer area 38, and the developed image is transferred to the transfer paper 44 in the transfer area 38. A separation sensor 64 is arranged slightly downstream of the transfer area 38 in the transfer paper conveyance direction, and the separation sensor 64 detects the presence or absence of the rear end of the transfer paper 44. The transfer sheet on which the developed image is transferred is conveyed to a fixing device (not shown) and fixed by a discharge roller (which is an example of the discharge device according to the present invention) 52 which rotates in the direction of arrow D by the main drive motor 12. Is discharged to the discharge tray 54,
One copy cycle is completed. Further, a paper discharge sensor 66 is provided on the downstream side of the discharge roller 52 in the transfer paper conveyance direction.
And the transfer paper 4 is
Presence / absence of the rear end portion of No. 4 is detected.

The image forming apparatus 10 is provided with a controller (which also serves as the first control device and the second control device according to the present invention) 60 for controlling the rotational speeds of the main drive motor 12 and the optical drive motor 32 described above. ing. The controller 60 will be described with reference to FIG.

FIG. 2 is a block diagram showing each device and the like controlled by the controller 60.

Each detection signal is input to the controller 60 from the optical scanning unit position sensor 31, the paper discharge sensor 66, the pre-registration sensor 62, and the separation sensor 64 described above. Further, the controller 60 is connected to the optical drive motor 32 via the optical drive motor driver 70, and transmits a signal carrying whether or not to rotate the optical drive motor 32 to the optical drive motor driver 70. Further, the controller 60 is connected to the main drive motor 12 via the main drive motor driver 72,
A signal carrying the speed at which the main drive motor 12 is rotated is transmitted to the main drive motor driver 72. Furthermore, the controller 60 is connected to a paper feed clutch 74 and a registration clutch 76 that connect and disconnect the power transmission of the main drive motor 12. The paper feed clutch 74 is connected to the paper feed roller 48 (see FIG. 1), and the registration clutch 76 is connected to the registration roller 50 (see FIG. 1). Therefore, the paper feed roller 48 and the registration roller 50 are respectively connected to each other. It is controlled by the controller 60 independently of the photoconductor drum 20. A plurality of other devices 78 are also connected to the controller 60.

Control by the controller 60 will be described with reference to FIGS. Here, the case where the number of copies is one will be described.

FIG. 3 is a flow chart showing the control when the transfer paper 44 (see FIG. 1) is conveyed toward the transfer area 38, and FIG. 4 forms an electrostatic latent image on the photosensitive drum 20. It is a flowchart which shows the control at the time.

When a copy request signal is input from the operation unit (not shown) of the image forming apparatus 10 in a state where the copying operation is possible, the CPU incorporated in the controller 60 (see FIG. 2) has the same configuration as that shown in FIGS. The program shown in 4 is executed. In the program shown in FIG. 3, first, it is determined whether or not to start copying (3-1).
This program ends (RET). When copying is started, the process proceeds to the next step, and it is determined whether or not the requested number of copies is one (3-2). When the number of requested copy sheets is not one, this program is terminated, and although omitted here, a normal copy operation is executed. When the requested number of copies is 1, the controller 60 (see FIG. 2) causes the main drive motor driver 72 to send the main drive motor 1
A signal indicating that the main drive motor 12 is rotating at double speed, and a signal indicating that the main drive motor 12 is rotating at double speed is input. Set (3-4),
This program ends. Although this signal input method is performed by switching the pulse frequency here, the switching signal is selectively output by the two signal lines, and the main drive motor driver 72 drives at one of two speeds. A speed control pulse for

When the main drive motor 12 starts to rotate at a double speed, the controller 60 turns on the paper feed clutch (see FIG. 2) 74, the paper feed roller 48 starts to rotate in the direction of arrow D, and the transfer paper 44 is transferred. Transfer area 38 (see FIG. 1)
To the registration roller 50. Transfer paper 44
When the front end portion of is detected by the pre-registration sensor 62, this detection signal is input to the controller 60, and the optical drive motor driver 70 rotates the optical drive motor 32. Here, the optical drive motor 32 is rotated at the timing of detection of the front end portion of the transfer paper 44 by the pre-registration sensor 62.
The optical drive motor 32 may be rotated by the passage of this timer. In this way, the transfer paper 44 is conveyed from the tray 46 to the registration roller 50 at a speed twice as fast as the process speed, and the copying speed is increased accordingly. In the above example, the case where the number of requested copies is 1 has been described.
The above program can also be applied to the first recording sheet for forming a series of images.

The program shown in FIG. 4 will be described.

As described above, this program is executed when the copy request signal is input. First, it is judged whether or not copying is in progress (4-1), and when copying is not in progress, this program is terminated. When copying is in progress, the process proceeds to the next step, and it is determined whether or not the main drive motor 12 is under double speed control (4-2). Main drive motor 1
When 2 is not under double speed control, this program ends, and when the main drive motor 12 is under double speed control,
Proceeding to the next step, it is judged whether or not the paper feed system flag is set (4-3). When it is determined that the paper feed system flag is set, it is determined whether the optical drive motor 32 is started (4-4). When the optical drive motor 32 has not started, this program is ended. On the other hand, when the optical drive motor 32 is started, the paper feed system flag is reset (4-
6) The main drive motor 12 is rotated at a predetermined speed so that the photosensitive drum 20 rotates at the process speed (4-7). In this way, the photosensitive drum 20 is rotated at the process speed from the start of forming the electrostatic latent image on the photosensitive drum 20 to the transfer of the developed image on the transfer paper. As described above, the optical drive motor 32 starts rotating at the timing when the front edge of the transfer paper 44 is detected by the pre-registration sensor 62.

When it is determined in step 4-3 that the paper feed system flag is not set, it is determined whether or not the transfer paper 44 is ejected. When the transfer paper 44 is not ejected, the main drive motor is driven. Continues the double speed control of and ends this program. On the other hand, when the transfer paper 44 is ejected, the main drive motor 12 is rotated at a predetermined speed (4
-7). Further, the flag indicating that the main drive motor 12 is rotating at double speed is reset.

The developed image is transferred to the transfer area 38 (see FIG. 1).
At the timing when the rear end portion of the transfer paper 44 is detected by the separation sensor 64 after being transferred to the transfer paper 44 in FIG.
Rotates the main drive motor 12 at twice the process speed so that the motor rotates at twice the process speed. As a result, the transfer paper 44 after the transfer is discharged outside the machine at a speed twice the process speed. When the transfer paper 44 is ejected, the ejection sensor 66 detects the ejection of the transfer paper 44, and Step 4- of FIG.
As shown in 7, the main drive motor 12 is rotated at a predetermined speed. However, whether or not the main drive motor is rotated at a predetermined speed after the recording paper is discharged depends on other reasons in the process, and thus may be stopped. In this way, after the transfer is completed, the transfer paper is ejected at a speed twice as fast as the process speed, so that the copying speed is increased accordingly.

[0027]

As described above, according to the first image forming apparatus of the present invention, the transfer material to be transferred to the transfer area this time is the first transfer of one or a plurality of series of image formation. In the case of material, from the timing of starting the conveyance of the recording paper to the timing of starting the formation of the electrostatic latent image,
Since the transfer material is conveyed toward the transfer area at a speed higher than the process speed, the copy speed increases accordingly.

Further, according to the second image forming apparatus of the present invention, when there is one transfer material conveyed to the transfer area this time, the transfer material is discharged from the timing when the transfer material passes through the transfer area. Until the timing, the transfer material is discharged at a speed faster than the process speed, and the copying speed increases accordingly.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention.

FIG. 2 is a block diagram showing each device controlled by a controller.

FIG. 3 is a flowchart showing a control when a transfer sheet is conveyed to a transfer area.

FIG. 4 is a flowchart showing control when an electrostatic latent image is formed on a photosensitive drum.

[Explanation of reference numerals] 10 image forming apparatus 20 photoconductor drum 38 transfer area 44 transfer material 48 paper feed roller 52 discharge roller 60 controller

Claims (2)

[Claims] 1. An electrostatic latent image is formed on an image carrier rotating at a predetermined process speed, the electrostatic latent image is developed with a developer, and the developed image is transferred onto a transfer material in a predetermined transfer area. In the image forming apparatus, a transfer device that transfers the transfer material to the transfer area and a transfer material that is currently transferred to the transfer area are the first transfer material of a series of one or a plurality of images. Between the timing of starting the transport of the recording paper and the timing of starting the formation of the electrostatic latent image, the transport device is configured to transport the transfer material toward the transfer area at a speed higher than the process speed. An image forming apparatus comprising: a first control device for controlling. 2. An electrostatic latent image is formed on an image carrier rotating at a predetermined process speed, the electrostatic latent image is developed with a developer, and the developed image is transferred onto a transfer material in a predetermined transfer area. In the image forming apparatus, the discharging device that discharges the transfer material onto which the developed image is transferred, and when the transfer material that is conveyed to the transfer area this time is one, the transfer material passes from the timing when the transfer material passes through the transfer area. An image forming apparatus, comprising: a second control device that controls the discharge device so that the transfer material is discharged at a speed faster than the process speed until the timing when the transfer material is discharged. .