JPH04248575A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate the need of repeating useless original size detection and simultaneously, to show an advantage that the original size detection is carried out by resetting an original size detection state when an original cover is opened, and the original is removed from an original platen. CONSTITUTION:This image forming device is composed of an original scale 32, the original platen 34, a first carriage 38a, first and second sensors 60a and 60b, a mode selecting key 31d, etc. Even if the original cover is opened after the first copying is carried out, the original size detection is not released when the original is placed on the original platen 34. Thus, when the same original is copied, again, the copying is quickly carried out.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention automatically detects the size of the document on the document table with the document cover open when placing the document on the document table, and then starts the image forming process. The present invention relates to an image forming apparatus.

0002

2. Description of the Related Art In recent years, image forming apparatuses such as electrophotographic apparatuses have been equipped with methods such as automatically selecting paper to be used for copying and determining whether the selected paper size is appropriate. Therefore, a device has been developed that detects the size of a document placed on a document table before copying starts.

[0003] In such an apparatus, a light reflection type sensor is generally used to detect the difference between the amount of light reflected from the document and the amount of light reflected from the platen sheet that coats the document by character. The size of the document is detected by identifying the document and the platen sheet.

However, in such an apparatus, the above-described document size detection operation has conventionally been performed by placing the document on the document table and then turning on the copy key to perform a copy operation in the document size detection mode. The copy operation was started by inputting a copy operation start signal. That is, a light reflection type sensor is usually used together with an exposure device, for example [A. 4] Waiting at a predetermined reference position corresponding to the rear end of the size. Then, when the copy key is turned on, the original is copied to [A. 4] If the size is smaller than the original size, the light reflection sensor detects the trailing edge of the document while moving toward the scan home position together with the exposure device. On the other hand, the manuscript [A. 4] If the original size is larger than the original size, the light reflection sensor moves together with the exposure device in the direction opposite to the scan home position, and detects the trailing edge of the original. After detecting the document size, the light reflection sensor and the exposure device are moved to the scan home position, and then the copying operation is started from the scan home position.

For this reason, when the original size is larger than the reference position, it takes a long time to copy the first sheet compared to normal copying when the original size is not detected, which increases the operator's waiting time and reduces operability. However, there have been problems in that the speed of copying is impaired, and furthermore, speeding up of copying is hindered.

Furthermore, in this device, the document size is detected with the document cover closed and the document covered with the platen sheet. The sheet needs to be colored. On the other hand, as the light emitting element of the light reflection type sensor, it is necessary to use a light emitting element having a wavelength band having a low reflectance with respect to the color of the platen sheet. Moreover, when setting the photoreceptor material, the color of the platen sheet, the color of the light emitting element, etc., the color of the platen sheet must be one to which the photoreceptor has high sensitivity so as not to affect the image during copying. This resulted in various restrictions.

For example, when an organic photoconductor is used as a photoreceptor, the color of the platen sheet is preferably yellow from the viewpoint of image formation, and the light emitting element having a low reflectance relative to yellow is preferably blue. is a light emitting element. E. In the case of D (light emitting diodes), etc., it is difficult to obtain ones that emit blue light, and the parts become expensive, resulting in increased costs. This has caused problems in terms of production and cost.

[0008]

[Problems to be Solved by the Invention] Conventionally, the operation for detecting the size of the original placed on the original platen is started by turning on the copy key, and copying starts after the completion of this size detection. If the size of the document exceeds the standard position where the machine is waiting, it takes time to copy the first page, which increases the operator's waiting time, impairs operability, and impedes copying speed. was there.

On the other hand, since the size of the original is detected while it is covered with a platen sheet, the platen sheet must be colored in order to distinguish it from the original, and the color must be suitable for the photoreceptor material. There is also the problem that there are mutual restrictions such as the photoreceptor material, the color of the platen sheet, the color of the light emitting element, etc., and this results in an increase in cost.

[0010] Therefore, the present invention aims to eliminate the above-mentioned problem. In the original size detection mode with the original cover open, it takes a long time to copy the first page even if the original is large. This improves the operability during copying, and there are no restrictions on the color of the platen sheet or the color of the light emitting element, regardless of the material of the photoreceptor, and there is no increase in costs due to the use of special parts. It is an object of the present invention to provide an image forming apparatus that can reliably detect the document size without any problems.

[0011]

[Means for Solving the Problems] In order to achieve the above object, an image forming apparatus of the present invention includes a document cover that covers a document, a document cover provided opposite to a document table, and a document cover on the document table. a first detecting means for detecting the presence or absence of a document; a second detecting means provided opposite to the document table and detecting the size of the document on the document table with the document cover opened; a setting means for selectively setting a document size detection mode that allows the document size detection operation by the detection means; and when the first detection means detects the presence of a document in accordance with the setting of the document size detection mode by the setting means; , and control means for starting the document size detection operation by the second detection means, and the document size detection state is reset when the document cover is opened and the document is removed from the document table.

0012

[Operation] By using the above-mentioned means, the present invention can detect the placement of a document on the document table while the document cover is open, instead of starting a copy operation by turning on the copy key as in the conventional case. , since the original size detection operation can be started, the time for copying the first sheet after turning on the copy key is the same regardless of whether the original size detection mode or original size ratio detection mode is used, and the operator's time when copying is reduced compared to the conventional method. Waiting time is reduced and operability is improved. Furthermore, even if the document cover is opened after the first copy, if the document is placed on the document table, the document size detection will not be canceled, so if you want to copy the same document again, you can copy quickly. . This eliminates the need to repeatedly perform unnecessary document size detection and maximizes the advantages of document size detection. Further, once the size of a document has been detected once, that document can be copied without having to detect the size again, regardless of whether the document cover is opened or not. This increases the chances of using document size detection. In addition, since the document size can be detected with the document cover released before copying starts, the detection means does not need to distinguish between the document and the platen sheet as in the past, and the detection means does not need to distinguish between the document and the platen sheet, regardless of the photoreceptor material. Restrictions on sheet color, light emitting element color, etc. are eliminated.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 10. FIG. 1 is a schematic explanatory diagram of the image forming apparatus 10, in which a photosensitive drum 1 located approximately in the center of the main body 11
2, a charging device 13, an exposure position 14a by an optical device 14, a developing device 16, a transfer peeling charger 17, a cleaning device 18, and a static elimination lamp 20 are provided. Further, on the right side of the main body 11, cassettes 21a and 21b for storing sheet paper P and a manual paper feed tray 21c are provided. Inside the main body 11, a pickup roller 22a,
Sheet paper P taken out and fed by 22b and 22c
A paper transport path 24 is formed that guides the paper through the photoreceptor drum 12 to a paper discharge tray 23 on the left side of the main body. On the upstream side of the paper conveyance path 24 from the photoreceptor drum 12, first and second
Separation rollers 25a, 25b and a pair of registration rollers 26 are provided, and a conveyor belt 27 and a pair of fixing rollers 26 are provided on the downstream side.
8. A pair of paper ejection rollers 30 is provided. Further, the upper surface of the main body 11 has a document table 34 on which the document D is placed, a white platen sheet 35a, and a document cover 3 that covers the document table 34.
5 is provided, and an operation panel 31 is also provided. This operation panel 31 is shown in FIG. On this operation panel 31, a display panel 31a, a copy key 31b, a numeric keypad 31c, a mode selection key 31d,
It is a setting means that is provided with a display section 31e, etc., and selectively sets whether or not it is a document size detection mode in which a first sensor 60a and a second sensor 60b, which will be described later, perform a document size detection operation. Mode selection key 3
1d is provided. A document scale 32 that serves as a guide when placing the document D is provided around the document table 34 on the leading edge side of the document.

Further, as shown in FIG. 3, the optical device 1
The first carriage 38a, which is a scanning means on which the No. 4 exposure lamp 36 and the first mirror 37a are mounted, includes a first sensor 60a, which is a second detection means, and which detects the document size in the document size detection mode; A second sensor 60b that serves both as a first detection means for detecting the presence or absence of a document and as a second detection means for detecting the document size in the document size detection mode.
is provided. These first and second sensors 60a,
60b, when detecting the size of the document D with the document cover 35 open, emits pulse-modulated light to prevent false detection due to external light such as fluorescent lights, as shown in FIG. The light modulation type reflective sensor includes a light emitting element 61 that receives light from the light emitting element 61, and a light receiving element 62 that receives only a specific pulse of light from the light emitting element 61. Furthermore, the first and second
The sensors 60a and 60b are provided at an angle θ with respect to the vertical direction in order to prevent false detection due to specular reflection from the document table 34.

Further, 38b is a second carriage 38b on which a second mirror 37b and a third mirror 37c are mounted, and the first and second carriages 38a and 38b are mounted on fixed first and second pulleys. [
It is designed to reciprocate at a speed of 2:1].

The first and second sensors 60a and 60b on the first carriage 38a scan along straight lines A-A and B-B, respectively, facing the document table 34, as shown in FIG. It is located in such a position that For example, [A. 5] From the size [A. 3]
It is possible to place originals D up to the original size, and all originals are placed so that the center 34a of the original platen 34 displayed on the original scale 32 is at the center of the original D.

Furthermore, the detection positions T, U, V, W, X, Y, and Z in FIG. 6 correspond to the first carriage 38a during size detection.
These detection positions T, U, V, W, X, Y
, Z, the respective output levels of the first and second sensors 60a, 60b are determined by a control device 70 which is a control means to be described later.

Further, as shown in FIG. 5, reference numeral 63 is a photo-interrupter type cover switch provided on the rear side of the document table, consisting of a light emitting element 63a and a light receiving element 63b, and is used to open and close the document cover 35. When the presence or absence of the actuator 64, which is oscillated in conjunction, is detected, and the opening angle of the document cover 35 becomes less than or equal to the angle α, and the cover switch 63 is turned on by lowering the actuator 64, the first and second sensors 60a, The size detection operation by 60b is prohibited. Note that this angle α is such that the first and second sensors 60a, 60b are
This is an angle to prevent the reflected light from the document D from being detected incorrectly as the reflected light from the document D, and is determined by the focal lengths of the first and second sensors 60a and 60b. .

FIG. 7 shows a block diagram of the control device 70, in which the processor group 70a receives signals from each operation key on the operation panel 31 or a paper detection switch (
Furthermore, signals from various switches/sensors 76 such as a cover switch 63 and a toner concentration sensor are input, and the originals detected by the light receiving elements 62 of the first and second sensors 60a and 60b are input. The reflected light from D is converted into an electrical signal and input. On the other hand, the processor group 70a controls the image forming means 77 such as the photosensitive drum 12 and the surrounding charging device 13 and the developing device 16, and also controls the scanning motor 41 via the pulse counter 71. The size of the document D is determined based on the signals input from the second sensors 60a and 60b. That is, a memory 72 is connected to the control device 70 in which various data used for determining the size of a document is stored. This memory 72 is a RAM (Random Access RAM) in which a detected position indicating the position of the first carriage 38a is stored according to the number of pulses by the pulse counter 71.
memory) 73, detection position and first and second sensors 60
It is constituted by a ROM (read only memory) 74 that stores identification data for determining the document size according to the combination with the output level of the output signals 60a and 60b.

FIG. 8 logically shows the identification data stored in the ROM 74. In the processor group 70a, the detected position of the first carriage 38a and the first
Various document sizes are determined based on the output levels of the second sensors 60a and 60b. This FIG. 8 shows the output level at each detection position of the first sensor 60a, which moves through the position of the document table 34 shown by the straight line A-A in FIG. The output level at each detection position of the second sensor 60b moving through the document table 34 position indicated by B-B is indicated by ◯ and ×. Here, a circle indicates a state in which the light-receiving element 62 receives reflected light from the original D, that is, a state in which the original D is detected, and an x indicates a state in which the light-receiving element 62 does not receive reflected light from the original D, in other words, the original This shows a state where D is smaller than the detected position.

Further, the processor group 70a is supplied with count data obtained by counting the number of pulses supplied to the scanning motor 41 from the pulse counter 71, and the processor group 70a stores the number of pulses supplied from the pulse counter 71 and the RAM 73. The position of the first carriage 38a is determined from the detection position in The size of the document D is determined from these determination results and the identification data in the ROM 74.

A flow chart of the present invention in the original size detection mode will be explained with reference to FIG. When the document cover 35 is closed, the cover switch 63 transmits information that the document cover 35 is closed and does not start size detection (STP1, 2).
. In the STP2 state, a message "Please set the original" is displayed on the display section 31e. manuscript cover
35 is opened, it is determined whether the document is placed on the document table (STP3). When it is determined that the document is placed on the document table, size determination is started (STP4). It is determined whether the document cover is closed while the size is being determined (STP5). If it is determined that the document cover is closed, the process returns to STP1 again. Furthermore, if the document cover is not closed, it is determined whether or not the size determination has been completed (STP6). If the size determination is not completed, the process returns to STP4. When the size determination is completed, it is determined whether the copy key 31b has been pressed (STP7). When the copy key 31b is pressed,
A normal copying operation is performed (STP8). Copy key 31b
If is not pressed, it is determined whether 30 seconds have passed after the size determination (STP9). If 30 seconds have not elapsed since the size determination, the process returns to STP7. Also, if 30 seconds have passed after size determination, auto-reset (S
TP10). After auto-resetting, return to STP1. After performing the normal copying operation in STP8, it is determined whether the document cover has been opened (STP11). If the document cover cannot be opened, it is held in the state of STP7. When the document cover is opened, it is determined whether the copy key 31b has been pressed (STP12). When the copy key 31b is pressed, a copying operation is performed at STP8. If the copy key 31b is not pressed, determine whether a document is placed (STP13)
. If no original is placed, return to STP3. Also,
If an original is placed, it is determined whether 30 seconds have passed after the copying operation (STP14). If 30 seconds have not elapsed since the copying operation, the process returns to STP12. If 30 seconds have passed since the copying operation, the process returns to STP3. As a result, the size of the original with the original cover 35 open is detected and a copying operation is performed.

According to the above flowchart, even if the document cover 35 is opened after the first copy, if the document is placed on the document table 34, the document size detection will not be canceled. , when copying the same original again, the copying can be done quickly. This eliminates the need to repeatedly perform unnecessary document size detection and maximizes the advantages of document size detection. Also, once the document size detection for the document is performed, the document cover 35
Regardless of whether the document has been opened or not, the document can be copied without having to detect the size again. This increases the chances of using document size detection.

Next, the operation will be described. When copying, the main body 11 is normally placed in an original size non-detection mode in which the sensors 60a and 60b do not perform the original size detection operation, and the first carriage 38a is in the [A. 4] Waiting at the reference position which is the rear end position of the size. When starting copying, if it is not necessary to detect the size of the original,
Immediately after placing the original D on the original platen 34, the operator turns on the copy key 31b and starts the copying operation. On the other hand, when it is necessary to detect the size of the document, the operator first turns on the mode selection key 31d on the operation panel 31, inputs the document size detection mode signal to the processor group 70a, and selects the mode of the main body 11. Each sensor 60a, 6
0b sets the document size detection mode in which the document size detection operation is performed. As a result, the processor group 70a drives the scanning motor 41 and moves the first carriage 38a along the flowchart shown in FIG.
from the reference position to the scan home position set near the document scale, and then move the first and second sensors 60a, 6
0b is placed on standby in a state where document size can be detected. However, when the cover switch 63 is on, the first and second sensors 60a and 60b are prohibited from detecting the document size.

After that, when the operator opens the document cover 35 to place the document D, the cover switch 63 is turned off due to the rise of the actuator 64, which causes the document size to be detected by the first and second sensors 60a and 60b. The detection prohibited state is canceled. Then, for example, [A] is placed on the document table 34.
．． 3] size original D is placed, the light receiving elements 62 of the first and second sensors 60a and 60b receive the light reflected from the original D from the light emitting element 61, and the original D is placed.
Detect. When an input signal indicating that a document is present from the second sensor 60b is input to the processor group 70a, the scanning motor 41 is immediately driven, and the first carriage 38a moves according to the direction indicated by the arrow in FIG. 1 in order to detect the document size. s
Scanning is started in the direction.

During this scanning, the output levels from the first and second sensors 60a and 60b at each detection position T to Z are determined by the processor group 70, as shown by diagonal lines in FIG. 9(a). Then, the document D is detected at all detection positions T to Z. As shown in FIG. 8, the reason why the document D is in the detection state at all the detection positions T to Z is that the document D is in the detection state at all the detection positions T to Z. 3]
The size of the document D is [A. 3] size.

Next, the operator closes the document cover 35, inputs various image forming conditions such as the number of copies, magnification, density, etc. as required from the operation panel 31, and then turns on the copy key 31b. As a result, a cassette with the optimal size of paper P is automatically selected based on the detected document size and image magnification, and a copying operation is started within the main body 11.

That is, in the main body 11, as the photosensitive drum 12 rotates, a toner image is formed through sequential charging, exposure, and development steps, and the toner image reaches the transfer separation charger 17. Meanwhile, in synchronization with this, paper P is fed from either of the selected cassettes 21a, 21b, passes through a pair of registration rollers 26, and is transferred to the transfer peeling charger 17 at the timing when the leading edge aligns with the toner image on the photoreceptor 12. sent. After the toner image is transferred, the paper P peeled off from the photoreceptor 12 is fixed by a pair of fixing rollers 28, and is discharged onto a paper discharge tray 23 by a pair of paper discharge rollers 30, thereby completing the copying.

On the other hand, after the transfer is completed, the remaining toner is removed from the photoreceptor 12 by the cleaning device 18, and the photoreceptor 12 is made ready for the next copy via the static elimination lamp 20, and the required number of copies is repeated. However, during this time, document size detection is prohibited and only copying operations are performed.

After completing the required number of copies, the operator takes out the original D from the original table 34 and places the next original.

After that, if copying of all originals is finished, the mode selection key 31d is turned off, and the main body is changed to the original size non-detection mode, the first carriage 38a
is [A. 4] It will wait for the next copy in a state where it is waiting at the reference position at the rear end of the size.

In the document size detection mode, when the document cover 35 is closed at an angle α or less with respect to the document table 34 and the cover switch 63 is turned on while the document size is being detected, the processor group 70a detects the document size. It is determined that this is not possible, and at the step STP1 of the flowchart, a size detection error message "Please set the original again" is displayed on the display section 31e of the display panel 31a.

FIGS. 9(b) to 9(h) show originals D of various sizes placed on the original platen 34.
), the first and second sensors 60a, 60b are
If document D is detected at all detection positions except for
The identification data in the figure shows that the manuscript D is [B. 4] Size
It is determined that Similarly, (c) to (h)
is [A. 4 horizontally placed], [B. 5 horizontally], [A.
4 vertically placed, [B. 5 vertical placement] [A. 5 horizontal placement], [A.
5 vertical position].

With this configuration, in the document size detection mode, by simply placing the document D on the document table 34,
Since the placement of the original D is detected and the original size detection operation is automatically performed, the original size detection operation is completed when the copying operation is started. Therefore, even in the original size detection mode, the time required to copy the first sheet is the same as in the original size non-detection mode, regardless of the original size. This reduces operator waiting time and improves operability.

Furthermore, when the original D is placed on the original platen 34, the size detection operation is performed immediately before the original cover 35 is closed. There is no need for identification, and the color of the platen sheet and the color of the light-emitting element 61 of the sensor are no longer subject to restrictions regardless of the characteristics of the photoreceptor, so there is no need to increase costs and it is possible to use a variety of photoreceptors according to the application. It is possible to use the body.

Furthermore, since the scan home position at which the size detection operation is started is near the original scale 32, if the original D is placed out of alignment with the original scale 32, the second
Since the original sensor 60b cannot detect the original and cannot detect the size, it is possible to reliably prevent erroneous size detection due to deviation of the original, and improve the reliability of size detection.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, the first detection means for detecting the presence or absence of a document and the second detection means for detecting the size of the document may be separately provided. However, in order to reduce the number of parts, reduce costs, and save space, it is preferable to use both the first detection means and the second detection means as in the embodiment.

[0038] The scan home position at which the document size detection operation is started is also arbitrary, and may be the rear edge position of the smallest sheet, but in order to prevent false detection due to document misalignment, it is recommended to is preferred.

Furthermore, the function of the control means is not limited; for example, if the original has many pages and it is input that the original size is to be stored in the memory, the function of the control means is not limited.
The size of the original document may be stored in the RAM. In this way, for documents after the second page, there is no need to perform a size detection operation every time the document is placed.

[0040]

[Effects of the Invention] As explained above, according to the present invention,
Since the original size detection operation is performed before the start of the copy operation, the first copy time is the same in original size detection mode and original size non-detection mode, and the operator's waiting time is longer even in original size detection mode. This improves the operability of copying. Furthermore, even if the document cover is opened after the first copy, if the document is placed on the document table, the document size detection will not be canceled, so if you want to copy the same document again, you can copy quickly. . This eliminates the need to repeatedly perform unnecessary document size detection and maximizes the advantages of document size detection. Further, once the size of a document has been detected once, that document can be copied without having to detect the size again, regardless of whether the document cover is opened or not. This increases the chances of using document size detection. Furthermore, when detecting the document size, in order to distinguish between the color of the document and the color of the platen sheet, the platen sheet is colored according to the sensitivity of the photoreceptor, and the emitted light color of the detection means is also considered accordingly. It is no longer necessary to use any photoreceptor material, and there is no need to limit the material of the photoreceptor at the time of design, which would result in an increase in the cost of the device, as was the case in the past, and it becomes possible to use any photoreceptor material.

[Brief explanation of the drawing]

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

FIG. 2 is a plan view of the operation panel of the image forming apparatus.

FIG. 3 is a schematic perspective view of a fog light device of an image forming apparatus.

FIG. 4 is a schematic explanatory diagram showing the state of detection by the first and second sensors.

FIG. 5 is a schematic explanatory diagram of the operation of the document cover.

FIG. 6 is an explanatory diagram of the detection position of the document table.

FIG. 7 is a schematic block diagram of the control system.

FIG. 8 is an explanatory diagram logically showing identification data stored in a ROM.

FIG. 9 shows the state in which originals of various sizes are placed on the original table; (a) shows [A. 3] size, (b) is [B. 4]
Size, (c) is [A. 4 horizontal placement] size, (d) is [
B. 5 horizontal placement] size, (e) is [A. 4 vertical position] size, (f) is [B. 5 vertical position] size, (g) is [A.
5 horizontal placement] size, (h) is [A. 5 Vertical] Diagram showing the size.

FIG. 10 is a diagram showing a flowchart of an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10... Image forming apparatus, 11... Main body, 12... Photosensitive drum, 14a... Exposure device, 32... Original scale, 34... Original table, 38a... First carriage, 60a... First sensor, 60b... Second Sensor, 61... Light emitting element, 62... Light receiving element, 31d... Mode selection key, 70... Control device.

Claims (1)

[Claims] Claim 1: A document cover that covers the document, and a first cover that is provided opposite to the document table and that detects the presence or absence of the document on the document table.
a second detection means that is provided opposite to the document table and detects the size of the document on the document table when the document cover is opened; a setting means for selectively setting a document size detection mode that allows a size detection operation; and a setting means for selectively setting a document size detection mode that allows a size detection operation; In the image forming apparatus, the image forming apparatus has a control means for starting the document size detection operation by the detecting means according to item 2, wherein the document size detection state is reset when the document cover is opened and the document is removed from the document table. An image forming apparatus characterized by: