JPH1110972A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of paper feed performance by performing control in self-starting region after slow-up driving of a stepping motor before detection of the forward end of a medium (recording sheet) at the time of paper feed retry operation. SOLUTION: A laser printer 1 comprises an image forming section, i.e., a process cartridge 7, where a toner image formed on a photosensitive drum 6 is transferred to a recording sheet 2 by applying a voltage to a transfer roller 4 and the toner image transferred onto recording sheet 2 is fixed by a fixing means 8. A decision is made that the paper feed operation has ended when a printer engine detects arrival of the recording sheet at a pair of registration rollers 3c. When it is not detected, a stepping motor 12 is stopped temporarily and paper feed operation is retried. In this regard, slow-up driving is performed in synchronism with the paper feed retry print timing and torque of the motor 12 is increased as compared with normal driving thus enhancing the paper feed capacity.

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 using a stepping motor as a drive source for conveying a medium.

[0002]

2. Description of the Related Art Heretofore, a paper feed retry operation means has performed a slow-up drive of the stepping motor, and when a predetermined number of revolutions has been reached, has shifted to a pull-out area drive.

[0003]

When a medium having a large load such as thick paper is fed, the feeding operation cannot be completed even if the feeding operation cannot be completed due to insufficient torque and the retry operation is started. Further, even if the paper feed retry functions due to the wear of the paper feeding unit, the paper feeding operation cannot be completed in some cases.

[0004]

In order to solve the above-mentioned problems, in the present invention, during the retry operation, paper feeding is performed by controlling the stepping motor in a self-starting area until the leading edge of the medium is detected after the stepping motor is driven up. This improves the reliability of performance.

[0005]

FIG. 1 shows a basic configuration of an image forming apparatus according to a first embodiment of the present invention. In the figure, 1 is a laser printer, 2 is a recording paper, 3a is a cassette, 3b
Is a feed roller, 3c is a registration roller pair, 4 is a transfer roller, 5 is an optical system for generating a laser beam, 6 is a photosensitive drum, 7 is a process cartridge, 8 is a fixing device, 9 is a discharge roller, and 10 is a discharge roller. A paper tray 11 is a printer controller. Reference numeral 12 denotes a main motor, which is a gear (not shown).
, The photosensitive drum 6, the process cartridge 7, the fixing device 8, the paper discharge roller 9 and the like are driven.

As shown in FIG. 1, the laser printer 1 irradiates a light source based on image information from an optical system 5 according to a control command of a printer controller to apply a developing material (hereinafter referred to as toner) to a photosensitive drum as an image carrier. Form an image. Then, in synchronism with the formation of the toner image, the stepping motor 12 is driven to convey the recording paper 2 from the cassette 3a by the conveying means 3 including a paper feed roller 3b, a pair of registration rollers 3c, and the like. Transfer roller 4 serving as a transfer unit for transferring the toner image formed on the photosensitive drum 6
Is transferred to the recording paper 2 by applying a voltage to the recording paper 2, and the recording paper 2 is conveyed to fixing means 8 having a built-in fixing heater 8 a, and the transferred toner image is fixed on the recording paper 2. The recording paper 2 is conveyed by a paper discharge roller 9 and is discharged to a paper discharge tray 10.

Here, the present invention will be described with reference to the drawings. The printer engine activates a stepping motor to start a paper feeding operation based on a print start signal from the printer controller. Next, the printer engine detects that the fed media (recording paper) has arrived at the registration rollers, determines that the paper feeding operation is completed, continues the print transport management, and if not detected, temporarily stops the stepping motor. Then, a paper feed retry operation is performed, and FIG.
The stepping motor is controlled as shown in FIG.

In FIG. 2, a slow-up drive is performed up to the rotation speed N2 in synchronization with the feed retry printing timing.
The paper feeding operation is started when the rotation speed N2 is reached. Next, when it is detected that the medium has reached the registration rollers, slow-up 2 drive is performed up to the rotation speed N1 and print conveyance management is continued. If the arrival of the medium at the registration rollers cannot be detected within a predetermined time, a paper jam is notified to the printer controller and the stepping motor is stopped. With the configuration described above, the stepping motor is driven in the slow-up 1 drive area and the pull-in drive area at the time of paper feed retry. At this time, as shown in FIG. 3, the torque of the stepping motor can output a torque T1 larger than the torque T2 during normal driving. As a result, even in a state in which the paper feeding performance cannot satisfy the original characteristics due to the paper feeding and conveyance of the medium having a large paper thickness and the wear of the paper feeding roller.
The paper feeding operation can be performed in the pull-in torque region.

[0009]

As described above, according to the present invention, even when the paper feeding performance cannot satisfy the original characteristics due to the paper feeding and conveyance of the medium having a large paper thickness and the wear of the paper feeding roller.
Since the paper feeding operation can be performed in the pull-in torque region, the reliability of the printer can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser printer 2 recording paper 3 a cassette 3 b paper feed roller 3 c registration roller pair 4 transfer roller 5 optical system for generating laser beam 6 photosensitive drum 7 process cartridge 8 fixing device 9 paper discharge roller 10 paper discharge tray 11 printer controller 12 main motor

Claims (2)

[Claims] An image forming apparatus using a stepping motor as a main drive source for conveying an image forming medium,
A feed retry operation unit for performing a feed operation more than once when feeding of the transport medium cannot be completed by the feed operation;
A driving unit for driving the stepping motor; and a rotation control unit for controlling a driving rotation speed of the stepping motor. During a paper feed retry operation of the image forming apparatus, the tip of the medium is driven after the stepping motor is driven up. An image forming apparatus wherein control is performed in a self-starting area until detection is performed. 2. The image forming apparatus according to claim 1, wherein
The rotation control means drives the stepping motor to perform a slow-up drive from the start of sheet feeding to a frequency during pull-in drive,
An image forming apparatus comprising: driving at a pull-in driving frequency until a leading edge of a medium is detected; and detecting the leading edge of the medium, and then performing slow-up driving to a predetermined number of rotations during normal driving.