JPH0820467A - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] To provide an image forming apparatus having a simplified structure and cost reduction. [Structure] When the output of the sensor 106 is turned off in step 407, the paper delivery control is started immediately (step 409). When the output of the sensor 106 is turned off, the timer is started again (step 41
0), it remains off (step 411), and when the predetermined timing is reached (step 412), it is judged as a delay jam. When the output of the sensor is turned on in step 411,
The timer is started again (step 413). Further, the movable plate 201 is immediately moved to the right until the sensor 106 is turned off (steps 414 to 416). After that, the movable plate 202 is moved to the left by a distance corresponding to the width of the sheet (step 417). At this time, the sheet S is exactly sandwiched between the two movable plates 201 and 202, and in this state, the sheet S is moved to the left by a predetermined amount (step 418), and the lateral registration adjustment control ends.

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 having a double-sided printing function.

[0002]

2. Description of the Related Art A conventional image forming apparatus such as a copying machine or a laser printer having a double-sided printing function is a switchback of paper (paper, film or the like medium on which an image can be recorded; the same in this specification). Timing means, paper jam detection means, registration in the direction perpendicular to the paper transport direction (hereinafter referred to as "horizontal registration").
,), But each of these means had its own individual sensor.

[0003]

However, providing a separate sensor for each of switchback, jam detection, and lateral registration complicates the configuration and increases the cost.

The present invention has been made to solve these problems of the prior art, and an object of the present invention is to provide an image forming apparatus having a simplified structure and cost reduction.

[0005]

The present invention is constructed as follows.

(1) In an image forming apparatus having a paper switchback mechanism, one detecting means for detecting the paper in the common path of the switchback mechanism, and the switchback timing of the paper based on the output of this detecting means. An image forming apparatus including a control unit that controls generation of a sheet, detection of a sheet jam, and adjustment of registration in a direction perpendicular to a sheet conveying direction.

(2) The control section generates the switchback timing by detecting the trailing edge of the sheet by the detecting means when the sheet is drawn into the common path of the switchback mechanism. Forming equipment.

(3) The control section is provided with a timer controlled by the output of the sheet detecting means, and judges the jam of the sheet when the timer reaches a predetermined value (1) or (2). Image forming device.

(4) The controller is provided with a pair of movable plates provided in a common path of the switchback mechanism and capable of moving a sheet passing therethrough in a direction perpendicular to the sheet conveying direction. The image forming apparatus according to any one of (1) to (3), which controls the operation of these movable plates based on the output of the sheet detection unit.

[0010]

The present invention is configured as described in (1) above, so that the timing of paper switchback is generated.
Jam detection and lateral registration can be adjusted with one sensor.

Further, with the configuration (2) above, by detecting the trailing edge of the sheet at the time of pulling in,
The timing of paper switchback can be generated.

Further, due to the above configuration (3), the jam of the sheet can be detected at a predetermined timing.

Further, by virtue of the configuration as described in (4) above, the lateral registration is adjusted by controlling the operation of the movable plate.

[0014]

EXAMPLES The present invention will be described below with reference to examples.

FIG. 1 is a schematic sectional view of a switchback mechanism of the electrophotographic printer of the embodiment. Reference numeral 101 is a paper drawing path, 102 is a sending path, and a branch point 103
Therefore, the side of the conveying roller pair 104 is a common path 105 through which the paper is both drawn and fed. Arrows a101 and a102 indicate the carrying directions at the time of retracting and sending out, respectively. Reference numeral 106 denotes a light transmission type sensor, which connects the light emitting element 106 (a) and the light receiving element 106 (b) to the common path 1.
It is arranged so as to face both sides of 05, and the presence or absence of a sheet is detected between the branch point 103 and the conveyance roller pair 104.

FIG. 2 is a diagram showing an operation of lateral registration adjustment according to the embodiment. Numerals 201 and 202 denote movable plates for adjusting the lateral registration of the sheet by moving the sheet in the horizontal direction in the figure with the sheet sandwiched therebetween.

Next, the operation will be described.

When the sheet S is being conveyed in the direction of arrow a201 (the direction of arrow a102 in FIG. 1 when the sheet is being fed out), the sensor 106 detects the leading edge of the sheet S when the sheet S is in the state of. After that, the left end of the paper S is detected when the movable plate 201 is moved rightward while the paper S is being conveyed (direction of arrow a202). Next, the movable plate 202 is moved to the left by a distance corresponding to the width of the paper S.
Finally, when the movable plates 201 and 202 are moved to the left by a predetermined amount (in the direction of arrow a203) and the sheet S is in the state, the control of the lateral registration adjustment ends.

FIG. 3 is a block diagram showing an electric circuit of the embodiment.

Reference numeral 301 denotes a printer controller,
Of these, 301 (a) is a central processing unit (CPU), 30
Reference numeral 1 (b) is an R storing a printer control program.
The OM 301 (c) is a RAM used for printer control, and these constitute a timer. Reference numeral 302 denotes a stepping motor M1 which is a driving source of the roller pair 104,
Reference numeral 303 denotes a stepping motor M2 which is a drive source of the movable plate 201, and 304 denotes a stepping motor M3 which is a drive source of the movable plate 202.

FIG. 4 is a flow chart showing the operation procedure of the embodiment.

The procedure of the jam detection, the paper switchback timing detection, and the lateral registration adjustment in the printer of the embodiment will be described in detail below with reference to the configurations shown in FIGS. 1 to 3 and the flowchart of FIG.

First, the movable plates 201 and 202 are moved to their home positions (step 401). This home position is a position where neither the left edge nor the right edge of the sheet abuts as shown in FIG. Since the sheet is conveyed to the pull-in path 101, the conveying roller pair 104 is started to be driven in the pull-in direction (step 402). Also, the printer controller 3
CPU 301 (a), ROM 301 (b), R in 01
The timer composed of AM301 (c) starts from the value "0" and starts counting up (step 40).
3). The output of the sensor 106 remains off (step 4
04) When the predetermined timing comes (step 40)
5) Judge as a delay jam.

If the output of the sensor 106 is turned on in step 404, the timer is restarted from the value "0" (step 406), but is kept on (step 407) and the predetermined timing corresponding to the paper length. If it becomes (step 408), it is determined that the jam is a jam.

If the output of the sensor 106 is turned off in step 407, the paper feeding control is started immediately (step 409). The path along which the sheet is conveyed is indicated by arrow a102 due to its structure. The feed-out control is a stepping motor M1 whose rotation direction is opposite to that of the pull-in control and whose speed is increased. Since the image forming process is not involved during the delivery control, the speed can be increased. The sensor 106 is also necessary to detect the timing of this switchback. When the output of the sensor 106 is turned off, the timer is restarted from the value "0" (step 410), but if it remains off (step 411) and the predetermined timing is reached (step 412), the delay jam is set. To judge.

When the output of the sensor is turned on in step 411, the timer is restarted from the value "0" (step 413). Immediately, the movable plate 201 is moved to the right until the sensor 106 is turned off (step 4).
14-416). Immediately thereafter, the movable plate 202 is moved to the left by a distance corresponding to the width of the sheet (step 41).
7). At this time, the paper S has two movable plates 201 and 202.
And is moved to the left by a predetermined amount in this state (step 418), and the control of the lateral registration adjustment ends.

If the output of the sensor 106 remains ON (step 419) and the predetermined timing corresponding to the paper length is reached (step 420), it is determined that there is a jam jam.

In the above operation, if it is judged that the jam is a delay jam or a jam jam, the jam processing is started.

(Modification of Embodiment) Instead of the light transmission type sensor 106, a light reflection type sensor may be used.

Instead of the light transmission type sensor 106, a photo interrupter using a movable flag may be used. Figure 5
[Fig. 6] is a diagram showing an operation of lateral registration adjustment when a movable flag is used, and Fig. 6 is a perspective view of the movable flag. Reference numeral 501 denotes a movable flag, and x501 indicates a rotation axis of the flag.

As shown in the figure, the movable flag is a sheet S.
Is arranged and configured so that it can move both in the conveying direction and in the direction perpendicular thereto.

[0032]

According to the present invention, the generation of the switchback timing of the paper, the detection of the jam, and the adjustment of the lateral registration can be performed by one sensor, so that the structure is simplified and the cost can be reduced.

Further, according to the second aspect of the present invention, by detecting the trailing edge of the sheet at the time of pulling in, the timing of the sheet switchback can be generated, and the sheet conveying speed is not affected. Easy to control.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a switchback mechanism according to an embodiment.

FIG. 2 is a diagram showing an operation of lateral registration adjustment according to the embodiment.

FIG. 3 is a block diagram showing an electric circuit of the embodiment.

FIG. 4 is a flowchart showing an operation procedure of the embodiment.

FIG. 5 is a diagram showing an operation of lateral registration adjustment of the embodiment using a movable flag.

FIG. 6 is a perspective view of a movable flag.

[Explanation of symbols]

 106 Light Transmissive Sensor 301 Printer Controller

Claims (4)

[Claims] 1. In an image forming apparatus having a paper switchback mechanism, one detecting means for detecting paper in a common path of the switchback mechanism, and a switchback timing of the paper based on the output of this detecting means. An image forming apparatus including: a control unit that controls generation, paper jam detection, and registration adjustment in a direction perpendicular to the paper conveyance direction. 2. The image according to claim 1, wherein the control unit generates the switchback timing by detecting the trailing edge of the sheet when the sheet is drawn into the common path of the switchback mechanism. Forming equipment. 3. The control unit comprises a timer controlled by the output of the paper detection means, and judges a paper jam when the timer reaches a predetermined value. The image forming apparatus described. 4. A pair of movable plates provided in a common path of a switchback mechanism and capable of moving a sheet passing therethrough in a direction perpendicular to a sheet conveying direction, wherein the control section is a sheet 4. The operation of these movable plates is controlled on the basis of the output of the detection means of FIG.
The image forming apparatus according to any one of 1.