JP2877595B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam printer capable of forming a multi-color image such as a full-color image or a multi-color image.
The present invention relates to an image forming apparatus such as an ED printer.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus using electrophotography, there has been provided a multicolor recording apparatus which forms a multicolor image in one or a plurality of recording cycles by sequentially performing charging, exposure and development steps. Have been. FIG. 8 shows a schematic configuration example of a conventional multicolor recording apparatus including a transfer drum and forming a multicolor image by a plurality of recording cycles, for example, a color laser beam printer.

[0003] In FIG. 8, the photosensitive drum 1 rotates steadily in the direction of the arrow, and moves along the rotating direction.
Charging device 7 for uniformly charging the toner, developing devices 3 to 6 each containing a different color developer (toner) for developing the latent image after exposure, and transferring the developed toner image to a recording material (paper). A transfer drum 2 for transferring and a cleaner 8 for removing residual toner on the photosensitive drum 1 are provided.

On the other hand, the transfer drum 2 as a recording material carrier is rotatably supported at the center thereof in a direction shown by an arrow in the drawing, and is in a state of being in contact with the surface of the photosensitive drum 1 or being slightly separated therefrom. To face the photosensitive drum 1. The transfer drum 2 is formed, for example, by cutting out the outer peripheral surface of a hollow drum housing only in a transfer area, and forming a cutout in the cutout by using a dielectric sheet typified by polyethylene terephthalate, polyvinylidene fluoride, fluoroethylene propylene copolymer or the like. It has a structure in which it is stretched as a support member, and holds the recording material 13 supplied from the paper feed cassette 25 via the registration roller pair 26 and the paper feed guide 27 by the gripper 22 and the suction roller 23, and electrostatically holds the recording material. Transport. Inside and outside the transfer drum 2, suction rollers 23 as means for electrostatically adsorbing the recording material 13 to the transfer drum 1, and grippers 22 for attaching the recording material 13 to the transfer drum 2 along the rotation direction. A bias applying device 14 for applying a transfer bias to the transfer drum 2, separation eliminators 9 and 10 for separating the recording material 13 onto which the toner image has been transferred from the transfer drum 2, assisting the separation, and Recording material 13
Claw 11 for guiding the toner to a recording material conveyance path for conveying the toner to the fixing device 15, a transfer drum cleaner 12 for removing toner adhered to the transfer drum surface after the separation of the recording material, and a transfer drum 2 (dielectric sheet) (Static discharge lamp) 20 for removing and initializing the transfer bias applied to the
Are arranged respectively.

The semiconductor laser 17 is driven by a video signal generated by a printer controller (not shown) based on an image signal from a host computer (not shown), and emits a laser beam 19. The laser beam emitted from the semiconductor laser 17 and modulated by the image signal is raster-scanned on the photosensitive drum 1 by the rotating mirror 18 through the imaging lens 16 and the reflection lens 21 to form an electrostatic latent image. The laser beam 19 is incident on an exposure position between the charger 7 and the developing devices 3 to 6.

The developing units 3 to 6 respectively store, for example, four color developers of yellow (Y), magenta (M), cyan (C) and black (BK), respectively.
In response to the electrostatic latent image formed on the photosensitive drum 1 by the laser beam 19, the developer, that is, the toner is electrostatically scattered from a selected developing device to develop the electrostatic latent image. To form a toner image of the selected color.

[0007] The multi-color recording apparatus having the above-described configuration, when power is turned on,
The transfer drum 2 is operated for a predetermined time, and then the transfer drum 2 is stopped, and waits for a print start signal from a host computer or a printer controller (not shown). After receiving the print start signal, a pre-rotation process of the photosensitive drum 1 and the transfer drum 2 in the image forming process is started, an image printing timing is obtained by the image leading end detection sensor 31, and an image signal from the host computer or the printer controller is obtained. To form a multicolor image based on
Then, after a predetermined multicolor image is formed, a post-rotation step of the photosensitive drum 1 and the transfer drum 2 in the image forming step is started,
After the completion of the rotation process, the transfer drum 2 stops.

FIG. 9 shows the power-on (O) of the multicolor recording apparatus.
9 shows a flowchart of a processing procedure from N) to reception of a print start signal. First, in step S51, it is determined whether or not the power has been turned on (including the case where the power is turned off once for the first time and the first power on, and then turned on again after the processing is completed). Judge,
If the power is on (YES), the process proceeds to step S52,
The transfer drum 2 is rotated, and in step S53, the transfer drum cleaner 12 and the neutralizer 20 are turned on. Next, in step S54, it is checked whether the cleaning and the charge elimination of the transfer drum 2 have been executed for one rotation of the transfer drum 2 (whether or not the time for one rotation of the transfer drum 2 has elapsed). If so (YES), the process proceeds to step S55, and the transfer drum cleaner 12 and the neutralizer 20 are turned off. Next, in step S56, the transfer drum 2 is turned off, and waits for reception of a print start signal (step S5).
7). When a print start signal is received (YES), the process shifts to step S58 to perform an image forming process such as turning on the transfer drum 2 and starting a timing for feeding the recording material 13, and the like.
A predetermined multicolor image is formed.

FIG. 10 shows a timing chart of a processing procedure from the power-on to the reception of the print start signal. Note that the timing chart in the figure is positive logic. Also,
t ₁ is the time required for the transfer drum 2 to make one rotation, and t ₂ is the time required from the reception of the print start signal to the start of paper feeding.

[0010]

However, in the conventional multicolor recording apparatus configured as described above for processing a multicolor image from a host computer (printer controller), when the power is turned on, the transfer drum 2 is cleaned, the charge is removed, and the transfer is performed. The transfer drum 2 is operated for a certain period of time for the purpose of discharging unnecessary recording material remaining in the multicolor recording apparatus in some cases, and the transfer drum 2 after this rotation operation is completed.
Is indeterminate, the position of the gripper 22 of the transfer drum 2 is also indeterminate (it can stop at any position). For this reason, the photosensitive drum 1 in the image forming process
And in the pre-rotation step of the transfer drum 2, the transfer drum 2
Must be rotated by a maximum of approximately one extra rotation, so that the time of the pre-rotation step is longer (t ₁ <t
₂ ) There is a disadvantage that the image forming processing speed is reduced.

Accordingly, it is an object of the present invention to provide an image forming apparatus in which the time required for the pre-rotation step in the image forming step is reduced and the image forming processing speed is increased.

[0012]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides an image carrier for carrying an image, a rotatable recording material carrier for carrying a recording material at a carrying start position, and a conveyance for conveying the recording material to the recording material carrier at a conveyance position. Means for transferring an image on the image carrier to a recording material carried on the recording material carrier, wherein a predetermined position of the recording material carrier on which a leading end of the recording material is carried And a control unit for controlling a stop position at which the recording material is conveyed from the conveyance position to the loading start position, and a time during which the predetermined position rotates from the stop position to the loading start position is equal to the time. An image forming apparatus comprising:

According to a preferred embodiment of the present invention, the recording material carrier is operated and kept at a predetermined position even after the apparatus is turned on and after the post-rotation process of the recording material carrier in the image forming process. And waits for reception of a print start signal.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The following embodiment shows a case in which the present invention is applied to an electrophotographic color laser beam printer.
The present invention can be applied to an image forming apparatus such as a copying machine or an image forming apparatus such as a printer or a copying machine other than the electrophotographic system.

FIG. 1 is a schematic diagram showing a first embodiment in which the present invention is applied to an electrophotographic color laser beam printer. Parts and members corresponding to those of the conventional color laser beam printer shown in FIG. 8 described above are denoted by the same reference numerals, and description thereof will be omitted unless necessary.

In this embodiment, a predetermined position detecting sensor 30 for stopping the transfer drum 2 at a predetermined position is provided.
The predetermined position detection sensor 30 is a position of the pair of registration rollers 26 as a conveying means for feeding the recording material 13 from the sheet cassette 25 at a predetermined timing, that is, a recording material carrying start position from the recording material conveying position. It is equal to the distance L1 to the mounting position of the transfer drum 2 (in this embodiment, the position of the gripper 22 for holding the leading end of the recording material 13), from this mounting position to the direction opposite to the rotation direction on the circumference of the transfer drum 2 At the position of distance L2.

The image leading end detection sensor 31 is a circle in the photosensitive drum rotation direction from an opposing position where the photosensitive drum 1 and the transfer drum 2 are in contact with or closest to each other to an exposure position where the laser beam 19 is incident on the photosensitive drum 1. The transfer drum 2 is installed at a position that is equal to the distance on the circumference and that is away from the facing position in the direction opposite to the rotation direction on the circumference of the transfer drum 2.

FIG. 2 shows a flowchart of a processing procedure from turning on the power of the multicolor recording apparatus of the present embodiment to receiving a print start signal. First, in step S51, it is determined whether or not the power has been turned on (including the case where the power is turned off once for the first time and the first power on, and then turned on again after the processing is completed). If it is determined that the power is on (YES), the process proceeds to step S52, in which the transfer drum 2 is rotated, and in step S53, the transfer drum cleaner 12 and the neutralizer 20 are turned on. Next, in step S54, it is checked whether the cleaning and the charge elimination of the transfer drum 2 have been executed for one rotation of the transfer drum 2 (whether or not the time for one rotation of the transfer drum 2 has elapsed). If so (YES), the process proceeds to step S55, and the transfer drum cleaner 12 and the neutralizer 20 are turned off. Next, the process proceeds to step S61, where the predetermined position detection sensor 30 checks whether or not the gripper 22 of the transfer drum 2 has reached the stop position.
S) The process proceeds to step S56 to turn off the transfer drum 2,
The process further advances to step S57 to wait for reception of a print start signal. When a print start signal is received (YES), the process proceeds to step S58, where the transfer drum 2 is turned on, and the recording material 13 is turned on.
The image forming process such as the start of paper feed timing is performed to form a predetermined multicolor image.

FIG. 3 shows a timing chart of the processing procedure of this embodiment from the power-on to the reception of the print start signal. Note that the timing chart in the figure is positive logic. Further, t ₃ is a time required from the rotation of the transfer drum 2 when the power is turned on to the stop of the transfer drum 2. The time t ₁ required for the transfer drum 2 to make one rotation and the gripper 22 by the predetermined position detection sensor 30 the sum of the time t ₅ to be detected that has reached the stop position. t ₄ after print start signal received, a time required to start the paper feed, in the present embodiment, the t ₄ ≒ t _1.

As described above, in this embodiment, after the transfer drum 2 performs one rotation operation when the power is turned on, the transfer drum 2 is stopped at a predetermined position, and waits for reception of a print start signal. When the image forming process is started after the reception of the print start signal, the time t ₄ until sheet feeding is t _4.
≒ the t _1. Accordingly, the pre-rotation step of the transfer drum 2 is reduced by a time corresponding to at most one rotation of the transfer drum,
In addition, since the processing time of the pre-rotation step is constant, there is a remarkable effect that the processing speed of image formation is further increased.

In the above embodiment, the transfer drum 2 is turned on when the power is turned on.
After one rotation, the transfer drum 2 is turned off at a predetermined position to wait for a print start signal, thereby shortening the processing time of the pre-rotation step in the image forming step. After the rotation process, the transfer drum 2 is turned off, and waits for reception of the next print start signal. Generally, the power supply of the device is used at the time of use (usually in the morning)
When it is turned on, it remains on until the end of the day's work. Therefore, after the first image forming process is performed, the above-described step of stopping the transfer drum 2 at a predetermined position is not performed. Therefore, as soon as the print start signal is received, the pre-rotation step is started again. But,
After the post-rotation step, when the transfer drum 2 is turned off, the position of the gripper 22 of the transfer drum 2 is not always the same, so that the processing time of the pre-rotation step may be delayed.

Therefore, in the second embodiment of the present invention, even after the post-rotation step is completed, the rotation operation is performed until the transfer drum 2 reaches a predetermined position, as in the first embodiment. It was done.

FIG. 4 is a flowchart showing a processing procedure from the post-rotation step of the multicolor recording apparatus of the present embodiment to the reception of the next print start signal to the image forming step. The basic configuration of the multicolor recording apparatus of this embodiment is the same as that of the first embodiment shown in FIG. 1 and is not shown, and the description thereof is omitted.

First, in step S62, it is checked whether or not the post-rotation process has been completed.
S), the transfer drum 2 is rotated (step S5).
2) Then, in step S61, the predetermined position detection sensor 30 checks whether the transfer drum 2 has come to a predetermined position (whether the gripper 22 of the transfer drum 2 has come to a stop position). If (YES), the process proceeds to step S56 to turn off the transfer drum 2, and thereafter, as in the first embodiment, proceeds to step S57 to wait for the reception of a print start signal.
ES) The process shifts to step S58 to turn on the transfer drum 2.
The image forming process such as the start of the timing of feeding the recording material 13 is performed to form a predetermined multicolor image.

As described above, in this embodiment, even after the post-rotation step is completed, the transfer drum 2 is rotated and stopped at a predetermined position. Therefore, in the image forming step after the power is once turned on. The processing time of the pre-rotation step becomes the same, and there is an effect that the processing speed of image formation is improved.

FIG. 5 shows a third embodiment of the present invention. Since the present embodiment is also applied to an electrophotographic color laser beam printer, parts and members corresponding to those of the color laser beam printer of the first embodiment shown in FIG. The description is omitted unless otherwise.

In this embodiment, a predetermined position detecting sensor for detecting that the transfer drum 2 has reached a predetermined position is not provided, but instead, the time from the image leading end detecting sensor 31 is used.
The transfer drum 2 is turned off at a predetermined position. In this embodiment, the image leading end detection sensor 31
It also has the function of detecting the leading edge of the image and the function of starting the counting of the transfer drum predetermined position stop counter. Hereinafter, the processing operation of this embodiment will be described with reference to FIGS.

FIG. 6 is a flowchart showing a processing procedure from power-on of the multi-color recording apparatus of the present embodiment to reception of a print start signal. FIG. 7 shows reception of the next print start signal from the post-rotation step. 4 shows a flowchart of a processing procedure up to an image forming step. In these flowcharts, the same processing steps as those in the flowcharts of FIGS. 2 and 4 are denoted by the same reference numerals.

When the power is turned on, the processing of steps S51 to S55 is performed in the same manner as in the first embodiment. That is, it is determined whether or not the power is turned on in step S51. If the power is turned on (YES), the process proceeds to step S52, in which the transfer drum 2 is rotated, and in step S53, the transfer drum cleaner 12 and the neutralizer 20 are removed. Turn on. Next, in step S54, it is checked whether the cleaning and the charge elimination of the transfer drum 2 have been executed for one rotation of the transfer drum 2, and if executed (YES), the process proceeds to step S55, and the transfer drum cleaner 12 Then, the static eliminator 20 is turned off. Next, the process proceeds to step S71, where it is checked whether or not the gripper 22 of the transfer drum 2 has been detected by the image leading edge detection sensor 31, and if detected (YES), the process proceeds to step S72, where the count of the transfer drum stop counter is counted. Is started, and the routine goes to Step S73. In step S73, it is determined whether or not the count value of the counter is the same as the value corresponding to the predetermined position at which the transfer drum 2 is stopped, that is, whether the distance L1 is smaller than the circumference of the transfer drum 2. It is checked whether it is the time required to pass the position of the distance L3 in the rotation direction from the position of the detection sensor 31, and if they match (YES), as in the first embodiment, step S56 is performed. To S58. That is, the process proceeds to step S57 to wait for the reception of the print start signal, and when the print start signal is received (Y
ES) The process shifts to step S58 to turn on the transfer drum 2.
The image forming process such as the start of the timing of feeding the recording material 13 is performed to form a predetermined multicolor image.

Further, when the post-rotation processing is completed, steps S62 and S5 are performed in the same manner as in the second embodiment.
2 is performed, and the transfer drum 2 is rotated. Next, it is checked whether the count value of the counter and the value corresponding to the predetermined stop position of the transfer drum coincide with each other in steps S71 to S73 in FIG. The processing of Steps S56 to S58 of Step 6 is performed to form a predetermined multicolor image.

As described above, the transfer drum 2 can also be turned off at a predetermined position by measuring the elapsed time from the image leading end detection sensor 31 at the recording material mounting position of the transfer drum 2. Since the processing time of the pre-rotation step is shortened and the processing time of the pre-rotation step becomes substantially constant, there is a remarkable effect that the processing speed of image formation is further increased.

In each of the above-described embodiments, the case where the present invention is applied to an electrophotographic color laser beam printer has been described. However, the present invention is applicable to other image forming apparatuses such as other electrophotographic printers and copiers. Can be applied to image forming apparatuses such as printers and copiers other than the electrophotographic type. Although the multicolor recording apparatus having a configuration in which a transfer drum is used as a recording material carrier is shown and described, the present invention is also applicable to an image forming apparatus having a configuration in which a belt-type endlessly moving recording material carrier is used. It goes without saying that you can do it.

[0033]

As described above, according to the image forming apparatus of the present invention, the control means controls the stop position where the predetermined position of the recording material carrier on which the leading end of the recording material is carried is stopped. Since the time during which the recording material is transported from the transport position to the carrying start position is configured to coincide with the time during which the predetermined position rotates from the stop position to the carrying start position, the predetermined position starts rotating from the stop position. From, it is possible to shorten the time until the leading end of the recording material is held at a predetermined position,
There is a remarkable effect that the processing speed of image formation can be further increased by a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment in which the present invention is applied to an electrophotographic color laser beam printer.

FIG. 2 is a flowchart showing a processing procedure in the first embodiment of the present invention.

FIG. 3 is a timing chart of a processing procedure in the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating a processing procedure according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a third embodiment of the multicolor recording apparatus according to the present invention.

FIG. 6 is a flowchart illustrating a processing procedure according to a third embodiment of the present invention.

FIG. 7 is a flowchart illustrating a processing procedure according to a third embodiment of the present invention.

FIG. 8 is a schematic configuration diagram illustrating an example of a conventional multicolor recording apparatus.

FIG. 9 is a flowchart illustrating a processing procedure in a conventional multicolor printing apparatus.

FIG. 10 is a timing chart of a processing procedure in a conventional multicolor printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor drum 2 Transfer drum 3-6 Developing device 12 Transfer drum cleaner 13 Recording material 14 Bias applying means 20 Static eliminator 22 Gripper 23 Suction roller 30 Predetermined position detection sensor 31 Image leading end detection sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03G 15/00 518 G03G 15/00 518 15/01 15/01 N 15/16 15/16 (58) Fields surveyed (Int. Cl ^6, DB name) G03G 21/14 G03G 21/00 370 -. 540 G03G 13/01 G03G 15/01 G03G 15/00 510 - 534 G03G 13/16 G03G 15/16 B65H 5/12

Claims (1)

(57) [Claims] An image carrier for carrying an image, a rotatable recording material carrier for carrying a recording material at a carrying start position, and a conveying means for conveying the recording material to the recording material carrier at a conveying position;
An image forming apparatus for transferring an image on the image carrier to a recording material carried on the recording material carrier, wherein a predetermined position of the recording material carrier on which a leading edge of the recording material is carried is stopped A control unit that controls a stop position, wherein a time during which the recording material is conveyed from the conveyance position to the loading start position is equal to a time during which the predetermined position rotates from the stop position to the loading start position. Characteristic image forming apparatus.