JPS60178111A - Endless belt - Google Patents

Abstract

PURPOSE:To securely detect the zigzag travelling of an endless belt in zigzag travelling correction control by adding zigzag travelling detecting marks having the width corresponding to the zigzag travelling allowance over the whole circumference parallel to the side end of the endless belt. CONSTITUTION:An endless belt, for example a light sensitive belt body OB, is stretched between a drive roller R1 and a driven rollers R2-R4 and driven in the direction A with a transfer sheet being closely attached to the surface of the belt. In this case, marks MK1 are attached to the light sensitive belt body OB parallel to the side edge S2 thereof over the whole circumference. And the width L of the mark MK1 is set correspondingly to the max. value of deflecting speed of said belt body OB and the zigzag travelling allowance related to the responsive time of zigzag travelling correction control. On the other hand, photosensors SS1, SS2 are arranged at an interval somewhat larger than the width L of the mark MK1. Thus, the mark MK1 is detected by the photosensors SS1, SS2 to judge securely the zigzag travelling of the light sensitive belt body OB.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an endless belt provided with meandering detection marks.

[Prior Art] In general, when it is necessary to hold the conveyed object on a flat surface, such as when conveying a sheet-like object (such as a sheet of paper), an endless belt (hereinafter referred to as an endless belt) is used as a conveying means. In many cases, a conveyance device using a

In such a conveyance means, since the endless belt itself, which serves as a member for placing (supporting) the object, forms a flat surface, it is relatively easy to hold the object in a flat surface.

FIG. 1 shows a drive unit for a belt photoreceptor, which is applied to an electrostatographic copying machine using a so-called belt photoreceptor as a sensor.

In this drive unit 1-, a belt photoreceptor OB is stretched between the drive roller R1 and the driven rows 512 to 81, and the belt photoreceptor OB is driven in six directions of arrows.

This device brings the transfer paper into close contact with the belt photoreceptor 9B, transfers the toner image formed on the photoreceptor from Pel 1 to the transfer paper, and then conveys the transfer paper to a fixing section.

By the way, as is well known, in such an endless belt drive device, so-called meandering development in which the endless belt shifts in its width direction always occurs.

The main reasons for this are that, for example, in the apparatus shown in FIG. It is mentioned that they are not completely parallel.

Therefore, conventionally, the meandering of the belt photoreceptor OB has been corrected by providing the roller R3 with the function of a meandering correcting roller.

That is, a photosensor PS1 that detects that the belt photoreceptor OB has meandered toward the side edge S1, and a photosensor PS2 that detects that it has meandered toward the side edge S2 are provided. The shaft is deflected in the direction of arrow B to move the belt photoconductor OB in the direction of arrow E. When sensor PS2 is turned on, the shaft of roller R3 is deflected in the direction of arrow C and belt photoconductor OB is moved in the direction of arrow E. let

By repeating this control one after another, the belt photoreceptor OB is prevented from coming off the roller.

By the way, the side edges S1 and S2 of the belt photoreceptor OB may come into contact with each copying process station arranged around the belt photoreceptor OB, the support mechanism supporting each roller R1 to R4, etc. If you use it for a long time, the side edge S
t, S2 may become partially jagged or have hangnails. ' When the belt photoreceptor OB is in such a state, the belt photoreceptor OB meanders and the sensors Psi and PS2 touch their side edges 3.
1 and 52, on-signals ONI to ON4 corresponding to the jagged and hangnail portions described above are output, as shown in FIGS. 2(a) and 2(b).

As a result, conventionally, there has been a problem that meandering detection in the above-mentioned meandering correction control becomes an uncertain operation.

In particular, the moving speed of the belt photoreceptor OB in the width direction (hereinafter referred to as
i-raR so as to gradually reduce the
When performing meandering correction control that deflects the axis No. 3, as the deviation speed decreases, the output period of the above-mentioned unnecessary ON signal becomes longer, making it increasingly difficult to correct the meandering.

Note that this inconvenience is not limited to the copiers mentioned above.
Similar problems occur in other devices that utilize endless belt drive devices.

[Objective] The present invention was made in order to eliminate the drawbacks of the prior art described above, and an object of the present invention is to provide an endless belt that can ensure meandering detection in meandering correction control.

[Configuration] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 shows a belt photoreceptor according to an embodiment of the present invention.

As shown, parallel to the side edge S2 of the belt photoreceptor OB,
A mark MKI is formed over the entire circumference, and photosensors 551 and 552 that detect the mark MKI are
The marks MKI are arranged at intervals slightly wider than the width of the marks MKI.

Normally, the belt photoreceptor OB is formed with a mirror surface and its surface reflects light well, so the mark 1 is formed by applying a black paint that does not reflect light or depositing a black substance. be done.

The width of the mark is set in accordance with the maximum value of the shifting speed of the belt photoreceptor OB and the meandering allowable amount related to the response time (responsivity) of the meandering correction control.

Also, this width and photo sensor S51. The difference from the interval of SS2 corresponds to the insensitivity* (that is, accuracy) of the meandering correction control.

The output signals of the photosensors SSI and SS2 are applied to a meandering correction control unit (not shown).

When the belt photoreceptor OB meanders toward the side edge S1, the photo
Since the photo sensor SS1 detects the mark MKI, its output signal changes, and when the belt photoreceptor OB meanders toward the side edge S2, the photo sensor SS2 detects the mark MKI, so its output signal changes.

As a result, the meandering correction control unit controls the belt photoreceptor OB.
It is possible to determine the meandering state of the

By the way, when it is necessary to know the driving status (speed, etc.) of the belt photoreceptor in meandering correction control, for example, if the belt photoreceptor O
When performing control to gradually reduce the deviation speed of B, a reference clock pulse for controlling the copying process is supplied to the meandering correction control unit.

Since this reference clock pulse is output from a pulse encoder attached to the main motor that drives the belt photoreceptor, special wiring is required if the meandering correction control unit is configured separately from the main control unit. Further, if the belt photoreceptor is slipping, there is a problem that the number of reference clock pulses does not correspond to the movement of the belt photoreceptor.

An embodiment that eliminates such inconvenience will be described below.

FIG. 5 shows a belt photoreceptor according to another embodiment of the invention.

In this embodiment, marks 2 are attached to marks A formed by alternately arranging strips M1 with a high density and strips M2 with a low density over the entire circumference parallel to the side edge SB2 of the belt photoreceptor OB.

Further, the photosensors 551 and 552 are connected to the belt photoreceptor O.
In the state where B is not meandering, both are arranged at positions where the mark MK2 is detected, as shown in FIG.

The output signals of the photosensors SSI and SS2 are waveform-shaped by a signal processing section, an example of which is shown in FIG. 7, and then output to the meandering correction control unit at the next stage.

The output signal of the photosensor SS1 is applied to a comparator CMPI to which a reference voltage Vr+ is set and a comparator CMP2 to which a reference voltage Vr2 is set.
The output signal of 52 is applied to a comparator CMP3 set to a reference voltage Vr+ and a comparator CMP4 set to a reference voltage Vr2.

As shown in FIG. 8(a), the reference voltage vr1 is larger than the output signal Sm1 of the photosensors SSI and S52 when one piece of material M1 is detected, and the photosensor when detecting one piece of material A2 551. The reference voltage vr2 is set to a value smaller than the output signal Sm2 of SS2, and the reference voltage vr2 is larger than the output signal Sm2 of the photosensors S51 and S52, and the photosensor 53 when detecting the belt photoreceptor OB.
It is set to a value smaller than the output signal sb of 1.552.

Therefore, when the photosensors S51 and S552 are detecting the old piece of material, the comparator C liver 1. On signal S from CMP3
01,5D3 (see FIG. 8(b)) is output, and the photosensor 551. When SS2 detects either piece M1 or M2, that is, mark MK2, comparator CMP2. CMI'
4 outputs an on signal SD2°SO2 (see FIG. 8(c)).

Now, when the belt photoreceptor OB is driven, each time the photosensors 551 and 552 detect the old piece, an ON signal S0 is generated.
1. If SO2 is output and the photosensor SS1 detects mark 2, the on signal SD2 is output.
is output, and if the photosensor SS2 is detecting the mark MK2, an on signal SD4 is output.

That is, the meandering correction control unit outputs the ON signal 501, S
The driving state of the belt photoreceptor OB can be determined from O2, and the ON signal SD2. The meandering state of the belt photoreceptor OB can be determined from SD4.

Therefore, according to this embodiment, it is not necessary to apply the reference clock pulse from the pulse encoder to the meandering correction control unit, and there is no need for wiring for this purpose.

[Effects] As described above, the present invention has the advantage that meandering can be reliably detected in meandering correction control.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional example of an endless belt. 2(a) and 2(b) are waveform diagrams showing an example of a meandering detection signal, FIG. 3 is a perspective view showing an embodiment of the present invention, and FIG.
The figure is a schematic diagram showing an example of the mark, FIG. 5 is a perspective view showing another embodiment of the present invention, FIG. 6 is a schematic diagram showing another example of the mark, and FIG. 7 is a signal processing section. FIG. 8(a) is a waveform diagram showing an example of level setting of the reference voltage, and FIGS. 8(b) and 8(c) are output waveform diagrams of the signal processing section. MKI, MK2...mark, old, M2...piece, S
51,552...Photo sensor, CM gate, CHF2.
CHF2. CHF2... Comparator. Figure 7 Hl Figure 2 Figure 3 Figure 5 Figure 1 Figure 7 Figure 8

Claims (1)

[Claims] On an endless belt that is stretched between multiple rollers, at least one of which acts as a meandering correction roller, and is driven by a motor, a meandering detection mark with a width corresponding to the meandering allowance is attached along the entire circumference parallel to the side edge. An endless belt characterized by: