JPH09300756A - Paper feed device in image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feed device in an image forming apparatus confirming the size of actually placed recording paper as it is and capable of immediately detecting the start of the feed of final one recording paper. SOLUTION: First and second prescribing plates 16a, 16b movable in a direction L1 and a third prescribing plate 17 movable in a direction L2 are arranged on a tray part 5 and sensors 18a, 18b, 18c are provided to the respective prescribing plates. For example, when A4 recording paper is placed on the tray part 5 in such a state that prescribing plates for an A4 size are set, the respective sensors 18a-18c detect the A4 recording paper at the same time and, for example, when B5 recording paper is placed, at least one sensor does not detect the recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device in an image forming apparatus, and more particularly to a sheet feeding device in an image forming apparatus capable of feeding recording sheets of various sizes by moving a regulation plate.

[0002]

2. Description of the Related Art Conventionally, some trays (paper feeding devices) of image forming apparatuses such as copying machines are of a type capable of feeding recording paper of various sizes. FIG. 14 shows a tray 1 of the type described above.
It is a top view including the partial cut part of 00. As shown in FIG. 14, the rectangular tray main body 101 has first and second regulation plates 102 and 103 for regulating the widthwise deviation of the recording paper along the sheet feeding direction, and the depthwise deviation. 3rd to do
The regulation plate 104 is arranged.

On the back side of the tray body 101, there are first and second
First and second drive levers 102a and 103a, which are connected to the regulation plates 102 and 103, are arranged. The first and second
A rack is formed at each of the tip ends of the drive levers 102a and 103a, and the pinion 105 meshed with the rack is formed.
The rotation of the first and second regulating plates 102 and 103 simultaneously moves in the directions of the arrows Y1 and Y2. Further, the first drive lever 102a includes a lever 106 of the slide resistor 106.
When a is directly connected and the first and second regulating plates 102 and 103 move in the directions of the arrows Y1 and Y2, the resistance value of the slide resistor 106 changes due to the movement of the lever 106a.
The movement amount of the restriction plates 102 and 103 is a control device (not shown).
Is made recognizable by.

The third restricting plate 104 is moved in the direction of arrow X, and this moving amount is transmitted to the slide resistor 107 via the drive lever 104a so that the moving amount of the third restricting plate 104 can be recognized by the control device. Has been done.

A reflection type recording paper detection sensor 108 is arranged in the main body of the image forming apparatus directly above the left end portion (the front end portion in the paper feeding direction) of the tray main body 101 and is mounted on the tray main body 101. It is possible to detect the presence or absence of the recording paper. Since this sensor 108 detects the presence / absence of all paper sizes, it is arranged directly above the central portion of the tip of the tray and can detect the presence / absence of recording paper of various sizes.

When the user places the recording paper (for example, A4 size) on the tray 100, each regulation plate 10
2, 103 and 104 are moved (set) to the A4 size position to secure a space for the A4 size, and the A4 size recording paper is placed in the space. By doing so, the control device of the image forming apparatus recognizes that the A4 size recording paper is placed on the tray based on the resistance values of the slide resistors 106 and 107, and performs various operations thereafter. It is a precondition for this.

[0007]

However, for example, it is assumed that the user has erroneously placed the A4 size recording sheet when the regulation plate is set to the A3 size. In this case, the control device of the image forming apparatus recognizes that the A3 plate is placed according to the position of the regulation plate of the tray and executes various processes. Therefore, the toner is supplied to the photoconductor drum in an amount corresponding to the size of the A3 plate, whereas the actual size of the recording paper is the A4 plate. Therefore, for example, the toner on the photoconductor drum is transferred onto the recording paper. Therefore, the transfer roller that is in pressure contact with the photosensitive drum is soiled by the untransferred toner in the [A3 plate-A4 plate] portion (see the hatched portion in FIG. 15A).

Further, as shown in FIG.
The distance between the second regulating plates 102 and 103 is set to A4 size (210 × 2
97 mm) in the longitudinal direction (297 mm), and the third regulating plate 104 is set in the lateral direction of the A4 plate (21 mm).
0 mm). Under the regulation plate set, the A3 size (297 x 420 mm) recording paper is
It is assumed that the second restriction plates 102 and 103 are placed in a lateral direction of 297 mm, and the longitudinal direction of 420 mm is placed so as to cover the third restriction plate 104.

Then, the control device of the image forming apparatus has about 210 m since the three restriction plates are set in the A4 size.
It is a normal operation to judge that the feeding of one sheet of A4 size recording paper is completed when m is conveyed, whereas when the image forming apparatus is used in such a state (a state where A3 is placed). A sensor (not shown) arranged in the main body of the apparatus for controlling the conveyance of the recording paper is A3 which is 210 mm or more during feeding.
The detection of the stencil sheet will be continued. Since this is equivalent to the occurrence of a jam for the control device, the control device recognizes that a jam has occurred and performs the jam processing (for example, stopping the device).

Further, even if the recording paper having the size of the regulation plate set thereon is placed, if the recording sheet is not placed at the proper position, the following inconvenience occurs. That is, when the recording paper is placed diagonally, the recording paper is skewed and an image is formed diagonally,
Also, if the amount of skew is large, a jam will occur. If the recording paper is placed in a state of being displaced in the front-back direction in the paper feeding direction, image defects and transfer roller stains occur. If the recording paper is placed behind the paper feeding direction, the paper feeding roller arranged at the front side in the paper feeding direction will be idle and the recording paper cannot be conveyed, resulting in a paper feeding failure. .

Furthermore, if the presence / absence of recording paper in the tray is detected at the leading end in the paper feed direction (sensor 108), the recording paper remains until the end of the last one recording paper passing through the sensor 108. Is recognized by the control device. Therefore, until the conveyance of the last one sheet is completed, the control device cannot recognize that the conveyance is completed, and the start of the next operation is delayed by the sheet feeding time for one recording sheet from the tray.

Therefore, an object of the present invention is to directly recognize the size of the recording paper actually placed and to detect the fact immediately when the conveyance of the last one recording paper is started. The present invention is to provide a sheet feeding device in an image forming apparatus capable of performing the above.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 is to move a tray on which a recording paper for feeding is placed, and to move the recording paper on the tray according to the size of the recording paper. In the sheet feeding device in the image forming apparatus including the regulating means for positioning the recording paper, the regulating means includes a recording paper detecting means for detecting the presence or absence of the recording paper.
According to the first aspect of the present invention, since the recording paper detecting means (sensor) is provided in the regulating means itself movable according to the size of the recording paper, it is possible to reliably detect the presence or absence of the recording paper. .

According to a second aspect of the present invention, when the recording papers are formed of standard materials having different sizes, the range in which the recording paper detection means detects the presence or absence of the recording papers is the range of the recording papers in the regulation means. Based on the part that regulates one end,
It is characterized in that the range is smaller than ½ of the minimum size difference among the sizes of the recording sheets to be placed.

According to the second aspect of the invention, the fixed form paper is
For example, as shown in FIG. 10, A2, A3, B4, A4
B5 and A5, and the minimum size difference among them is A4 (21
It is 28 mm which is the difference between 0 mm) and B5 (182 mm).
1/2 of this 28 mm is 14 mm, which is shown in FIG.
As shown in (b). If the reading range of the recording paper detection means (sensor) is larger than 14 mm, A4 and B5 cannot be discriminated (see FIG. 9B), and 14 mm
If it is less than A4, A4 and B5 can be identified (see FIG. 9A).

According to the third aspect of the invention, the recording paper detecting means provided in the regulating means arranged on the rear end side in the conveying direction of the recording paper also serves to detect the remaining amount of the recording paper on the tray. It is characterized by According to the third aspect of the present invention, for example, as shown in FIG.
Since c) is arranged at the rear end side of the recording paper (A4 recording paper) in the conveying direction, the last stacked A4 recording paper is the sensor 1
Immediately after the passage of 8c is completed, it is recognized that the recording paper will run out, and the control device of the image forming apparatus can immediately perform the next operation when the remaining amount of the recording paper is zero.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an external perspective view of a copying machine of this embodiment, and FIG. 2 is a perspective view of a multi-feed tray of the copying machine.

In FIG. 1, 1 is a pressure plate for holding a document, 2 is a platen glass on which a document is placed, 3 is an operating unit equipped with keys and a display unit (operating screen), and is operated by operating the operating unit. The ACC function, which will be described later, can be executed, 4 is a tray for loading recording paper, and 5 is a multi-feed tray (paper feeding device; hereinafter referred to as tray) on which various recording paper sizes can be set.

As shown in FIG. 2, first and second regulating plates 16a and 16b having L-shaped cross sections for regulating the side direction of the recording paper are arranged opposite to each other along both upper and lower sides of the upper surface of the tray 5, and the center thereof is slightly A third regulation plate 17 having an L-shaped cross section for regulating the rear end portion of the recording paper is arranged on the right side. The first and second regulation plates 16a and 16b are movable in the L ₁ direction orthogonal to the sheet feeding direction, and the third regulation plate 17 is movable in the L ₂ direction which is the sheet feeding direction.

FIG. 3 is a three-sided view of the first regulation plate 16a. As shown in FIG. 3, the first reflection type sensor 18a is attached to the leading end of the first regulation plate 16a in the sheet feeding direction. ing. A second reflective sensor 18b is also attached to the tip of the second regulation plate 16b in the sheet feeding direction.

FIG. 4 is a three-sided view of the third regulating plate 17. As shown in FIG. 4, a third reflective sensor 18c is attached to the rear end of the third regulating plate 17 in the sheet feeding direction. Has been.

Further, a slide resistor similar to the conventional example is arranged on the back surface of the tray portion (see FIG. 13), and the width of the recording paper can be detected by moving the first and second regulating plates 16a and 16b. By moving the third regulation plate 17, the length of the recording paper can be detected.

FIG. 5 is a block diagram of a control system related to the tray 5 in the copying machine. In FIG. 5, 3 is the operation unit, 7 is a drive system for various motors, clutches, solenoids, etc., 8 is a signal from various sensors 18a to 18c and a control signal to the drive system 7 for exchanging with the CPU 9. I / O interface for control, 9 is C for various controls
PU.

Further, 10 is a ROM in which a program for performing a series of operations required for copying is stored, 13 is a signal from the sensors 18a to 18c, and the presence or absence of recording paper,
RAM for warning judgment, size confirmation and storage, 1
Reference numeral 4 denotes a sensor and various switches for detecting the temperature of the fixing device, the temperature inside the device, the paper detection at each place on the recording paper conveyance path.

Next, the operation of this embodiment will be described. (1) Flow chart (see FIGS. 6 and 7) For example, in FIG. 2, the first to third regulating plates 16a, 16b, 17 are set at predetermined positions for placing the A4 size recording paper. Suppose A in this set
4 When the recording paper is placed on the tray 5 at the regular regulation plate setting position and the copy start key of the operation unit 3 is pressed, the paper size detection mode sequence starts, and the three sensors 18a, 18b, 18c Both detect A4 recording paper (step S1; YES). The recording paper detection signals of these three sensors are sent to the CPU 9, and the CPU 9 recognizes that the placed recording paper is A4, determines the recording paper size (step S2), and performs normal processing (normal copying). ) Is performed (step S3).

If all of the three sensors 18a, 18b, 18c do not detect the A4 recording paper in step S1 (step S4; YES), the setting position of the regulation plate and the recording paper size do not match [for example, , FIG. 8 (a)
As shown in FIG. 5, when the A5 recording sheet is placed at a position that is not detected by the sensor with respect to the A4 restriction plate set], the recording sheet is not placed (there is no recording sheet, so 3 sensors do not detect) (Step S
5).

If one or two of the three sensors 18a, 18b, 18c detect the recording paper in step S4 (step S4; NO), the regulation plate and the recording paper size match. If not [eg
As shown in FIG. 8B, when one side of the recording sheet of A5 is detected by the sensor 18a for the set of A4] (step S6).

In the case of steps S5 and S6, abnormal processing such as issuing an alarm is performed (step S7). Depending on the model of the copying machine, the auto cassette change function [ACC function: recording paper of the same size (for example, A4 size) is placed in a plurality of paper feed stages, and the recording paper of the paper feed stage designated at the time of copying is started. In the case where the sheets have run out before the completion of copying, a function for automatically changing the sheet feeding port to another sheet feeding tray on which the same size recording sheets are placed and continuing the copying operation may be provided.

In the conventional copying machine, the sensor 108 shown in FIG. 14 detects that the recording paper on the tray has run out before the completion of copying. In the present embodiment, since the sensor 18c is provided on the regulation plate 17 located at the rear end of the recording paper in the tray, the last paper feeding of the stacked recording papers can be detected immediately after the last paper starts moving, and immediately. Can activate the ACC function. Therefore, it is effective in preventing the delay of the copy time during continuous copying.

This sequence will be described with reference to the flow chart (see FIG. 7). During continuous copying, the three sensors of the regulation plate all detect the recording paper (step S11). At this time, if the sensor 18c of the regulation plate 17 detects that there is no paper (step S12; NO), the recording paper is exhausted, so the ACC function is activated (step S13), and another paper feed tray (tray) from that time is replaced. If control is performed to switch to the paper feed stage, it becomes possible to continue copying immediately. As described above, since the last paper is fed from the tray and the paper detection can be performed, continuous copying is not stopped. Therefore, the copy time is not delayed.

(2) Range read by the sensor For example, as shown in FIG. 9A, the first and second regulating plates 1
The distance between 6a and 16b is A4 in the lateral direction (210 m
m) and the B5 recording paper is placed in this state. In this case, the sensors 18a, 18
The reading range of b is R1 (for example,
Within the range of 2 mm), when the regulation plate is set in the state shown in FIG. 9A, the A4 recording paper and the B5 recording paper can be discriminated. Further, as shown in FIG. 9B, the above-mentioned reading range is R2 (for example, 20 m from the regulation surface).
Within the range of m), it is impossible to distinguish between A4 recording paper and B5 recording paper.

On the other hand, if the reading range is extremely narrowed from the regulation surface (for example, 1 mm from the regulation surface), variations in the setting positions of the regulation plates 16a and 16b, variations in the width of the recording paper, etc. are absorbed to cope with the problem. You may not be able to. Therefore, it is necessary to clarify the reading range.

By the way, the size of the standard paper used in a general copying machine is A2, A3, B as shown in FIG.
There are 6 types, 4, A4, B5 and A5. When these recording papers are placed between the regulation plates set with the respective standard lengths, it is necessary to identify the one having the smallest length difference between the recording papers. From this point of view, the A4 (210
mm) and B5 (182 mm), which is 28 mm, and one side has 14 mm. Therefore, if the difference in the lateral direction between A4 and B5 can be identified, the difference between other sizes can be identified.

Next, the reading range of the sensor for surely identifying the difference between A4 and B5 in the lateral direction will be described. FIG. 11 (a)
Shows the case where the distance between the first and second regulation plates 16a and 16b is set to the length in the lateral direction of A4, and the recording paper of B5 is placed on the left and right equal intervals. In this case, the distance from the left and right edges of the B5 recording paper to the regulation surface is R3 = 14 m, respectively.
m (critical value). If the reading range is a value (less than) smaller than this 14 mm, it is possible to distinguish between A4 recording paper and B5 recording paper.

For example, as shown in FIG. 11 (b), if the reading range (hatched) is less than the critical value (less than R3), even if the sensor 18b on the second regulating plate 16b side can read, the first It cannot be read by the sensor 18a on the side of the regulation plate 16a. First and second restriction plates 16a, 1 for A4
Even if 6b is set, it is possible to recognize that the placed recording paper is smaller than A4.

As shown in FIG. 12, it is assumed that A3 recording paper is placed when the first and second regulating plates 16a and 16b are set for A4. In this case the first
If the detection lengths of the second sensors 18a and 18b are long (indicated by a dotted arrow), there is a possibility that the A4 recording paper is mistakenly recognized as being properly placed. Therefore, a short sensor is suitable for the detection length as shown by the solid arrow.

Further, as shown in FIG. 13, it is assumed that the regulation plates 16a and 16b are set for A4 recording paper and the A4 recording paper is placed. Then, the last remaining recording paper is conveyed and, as shown by the chain double-dashed line, the trailing edge of the recording paper is at the third position.
If the detection range of the reflection type sensor 18c is exceeded, the CPU 9
(See FIG. 5) immediately recognizes that the last recording sheet is being fed, and can enter the operation necessary for switching to the next sheet feeding stage by, for example, an automatic cassette changer. That is, since the sensor 108 (see FIG. 14) is conventionally installed on the front end side in the sheet feeding direction as described above, the time until the last recording sheet leaves the tray main body 101 is lost time. According to the form example, it is possible to eliminate the lost time substantially.

[0038]

As described above, according to the invention described in each claim, since the regulating means includes the recording paper detecting means for detecting the presence or absence of the recording paper, the recording paper actually placed can be immediately detected. The recording paper read by the recording paper detection means is a standard material, and the reading range of the recording paper detection means is
Since the range is smaller than 1/2 of the minimum size difference of the standard-sized material in the size of the recording paper placed from the recording paper restriction surface of the restricting means, as shown in FIG. In addition, since the means for detecting the presence or absence of the recording paper, which is provided in the regulating means arranged at the rear end side of the recording paper in the conveying direction, also serves to detect the remaining amount of the recording paper on the tray, As shown in 13, it can be recognized immediately after the last recording sheet is started to be conveyed.

[Brief description of drawings]

FIG. 1 is an external perspective view of an exemplary embodiment of the present invention.

FIG. 2 is a perspective view of the tray according to the embodiment.

FIG. 3 is a three-sided view of a regulation plate used for the tray.

FIG. 4 is a three-sided view of another restriction plate used for the tray.

FIG. 5 is a block diagram of the embodiment.

FIG. 6 is a flowchart of the example of the embodiment.

FIG. 7 is another flowchart of the embodiment.

FIG. 8 shows a case where the tray regulation plate of the embodiment is set for A4, and (a) shows a case where A5 recording paper is placed at a position where it is not detected by all the sensors. )
FIG. 4 is a diagram showing a case where A5 recording paper is placed at a position detected by one sensor.

9A and 9B are views for explaining the reading range of the sensor in the embodiment, in which FIG. 9A is a case where A4 recording paper and B5 recording paper can be reliably identified, and FIG. 9B is A4 recording paper and B5.
It is a figure which shows each when a recording paper cannot be distinguished.

FIG. 10 is a diagram showing the size of the standard paper used in the embodiment.

FIG. 11 is a diagram for explaining a reading range of the sensor in the embodiment, in which (a) shows a critical value of the reading range necessary for surely discriminating between A4 recording paper and B5 recording paper. , (B) are diagrams respectively showing a case where the A4 recording paper and the B5 recording paper can be surely discriminated under the critical value.

FIG. 12 is a diagram illustrating a reading distance of a sensor in the example of the embodiment.

FIG. 13 is a diagram illustrating a state immediately after the last recording sheet is separated from the placement position in the embodiment.

FIG. 14 is a diagram illustrating a configuration of a conventional paper feeding device (tray).

FIG. 15 is a diagram illustrating an inconvenience of a conventional paper feeding device.

[Explanation of symbols]

 5 Multi Paper Feed Tray (Tray) 9 CPU 16a, 16b Regulation Plate (Regulation Means) 17 Regulation Plate (Regulation Means) 18a-18c Sensors (Recording Paper Detection Means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B65H 1/04 326 B65H 1/04 326B 7/14 7/14 G03G 15/00 516 G03G 15/00 516

Claims (3)

[Claims] 1. A paper feeding device in an image forming apparatus, comprising: a tray on which a recording paper for feeding is placed; and a regulation means for moving and positioning the recording paper on the tray in accordance with the size of the recording paper. The sheet feeding device in the image forming apparatus, wherein the regulation unit includes a recording sheet detection unit that detects the presence or absence of the recording sheet. 2. When the recording papers are formed of standard materials of different sizes, the range in which the recording paper detection means detects the presence or absence of the recording papers is based on the portion of the regulation means that regulates one end of the recording papers. 2. The sheet feeding device in the image forming apparatus according to claim 1, wherein the range is smaller than 1/2 of the minimum size difference among the sizes of the recording sheets to be placed. 3. The recording paper detecting means provided in the regulating means arranged on the rear end side in the conveying direction of the recording paper also serves as detecting the remaining amount of the recording paper on the tray. Alternatively, the sheet feeding device in the image forming apparatus according to claim 2.