JPH02309372A - Copying machine - Google Patents

Abstract

PURPOSE:To prevent failure in a driving system before it occurs by not having any excessive force work on the driving system by detecting when an original which exceeds in weight is placed on an original platen and stopping the copying action. CONSTITUTION:In this copying machine, weight data detected by four weight load sensors 92 is summed up and calculated at an analog adding device 95, and the absolute weight of an original is displayed digitally on a count displaying device 99. Because of this, analog signal concerning the weight of the original calculated at the analog adding device 95 is transformed to a digital signal at an A/D transformer 96, after it is passed through a switching circuit 97 and inputted into a display driving circuit 98, and the weight of the original is displayed digitally on the count displaying device 99. Therefore, it is made known to the user that the original placed on the original platen 4 is exceeding in weight by the lighting up of a warning lamp 100 and the original weight display which has been mentioned before.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copying machine with a movable document table, and particularly to a small copying machine suitable for personal use.

(Prior Art) Personal copying machines used in homes and the like are generally required to be inexpensive and compact. A copying machine with a movable document table that can scan documents with a relatively simple structure is suitable for this purpose. The applicant developed a compact personal copying machine that could be made sufficiently thin by selecting the production process and skillfully arranging the image-forming equipment accordingly, and filed a patent application for this machine (Japanese Patent Application No. 170-492-1982). No.~17049
No. 8).

(Problems to be Solved by the Invention) However, when pursuing a smaller size and lower manufacturing costs, such as the above-mentioned copying machine, the driving force of the device is limited, and the driving force for moving the document table is limited. You won't be able to get enough of it.

For this reason, if the original to be copied is too heavy, the movement of the original platen will not be smooth, which may cause a problem in the drive system.

In addition, by pursuing miniaturization of copying machines, the main body of the copying machine is made smaller and lighter, so that when the original platen slides to the position where it most protrudes from the main body of the copying machine, the originals on the original platen overlap. If too much is used, an imbalance will occur, and in extreme cases, the entire copying machine will lose its balance and tip over.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a means for detecting the weight of an original in a copying machine with a movable original table, and a means for disabling the copying operation when the weight of the original exceeds a predetermined load. The method is characterized by comprising a copy restriction means.

Further, the present invention is characterized in that, in place of the copy restriction means, a warning means is provided which issues a warning signal when the weight of the document exceeds a predetermined load.

(Function) According to the present invention, when an excessively heavy original is placed on the document table, it can be detected by the detection means, and based on this, the copying operation can be disabled by the copy restriction means, or the warning means can be activated. By issuing a warning signal to that effect, the copying operation can be stopped at the user's discretion. Therefore, it is possible to prevent excessive force from acting on the drive system that drives the document table, and to prevent failure of the drive system.

Furthermore, the problem of the entire copying machine tipping over due to unbalance caused by an excessively heavy document can also be prevented.

(Example) An example of the present invention shown in FIGS. 1 to 10 will be described.

As shown in FIG. 5, a belt-shaped photoreceptor 2 is provided approximately in the center of a flat body 1. The belt-shaped photoreceptor 2 is stretched in a horizontally long flat state by driven rollers 3a and drive rollers 3b arranged on the left and right sides. A movable document table 4 is provided on the body 1. The document table 4 is moved by the drive of a pinion 6 on the machine body 1 side that engages with a rack 5 provided thereon.

FIGS. 1 and 2 show a document table moving mechanism and a document weight detection mechanism. The document table 4 consists of a document glass 4a made of transparent glass, and frame members 4b and 4c arranged on the left and right sides.
It is slidably arranged on the upper plate 1a of the fuselage 1 via left and right slide rails 90,90. The slide rail 90 includes an upper rail 90a, a lower rail 90b, and a ball 90.
As is well known, it has a structure in which a loaded upper rail 90a is slidably supported on a lower rail 90b fixed to the upper plate 1a.

The left and right upper rails 90a, 90a are attached to the left and right frame members 4b, 4c of the document table 4 so that their movement in the front, back, left and right directions is completely restrained, and a slight movement in the up and down direction is allowed. The pinion 6 is driven by a drive gear 91 of a drive system.

The frame member 4b14c and the upper rails 90a, 90a
A load sensor (means for detecting the weight of the original) 92 is connected between the
is arranged so that the total weight of the original platen 4 and the originals placed thereon can be detected. Since the weight of the document table 4 is known, the weight of the document can be detected using the load sensor 92. And in this example,
As shown in FIG. 1, using four load sensors 92,
The weight of each of the four corners of the document table 92 at the initial position is measured. Note that as the load sensor 92, for example, a load cell can be used.

The control circuit shown in FIG. 3 shows what kind of processing is performed after the weight of the document is detected by the load sensor 92.

The output of each load sensor 92 is amplified by an amplifier 93 and input to a switching circuit A94. Each switching circuit A94 is normally in the ON state, but if the document is heavy, such as a thick dictionary, the output of the load sensor 92 will exceed a certain value, and the input value input to the switching circuit A94 will change. When it exceeds a certain value, it becomes OFF state.

When the switching circuit A94 is OFF, even if the print switch 101 is ON, no print signal is transmitted to the drive control system, making copying impossible.

The copy restriction means of this embodiment is basically configured as described above, but more specifically, as shown in FIG. The configuration is such that copy operations are disabled even when Therefore, even if the absolute weight of the original is within a certain value, the copying operation may become impossible if the original is placed in an deviated position. This is because the purpose of detecting the weight of the document is to ensure smooth movement of the document table and stability of the device during scanning operation, so this is a result of making it more in line with this purpose.

In this embodiment, the weight data detected by the four load sensors 92 is aggregated and calculated by the analog adder 95, so that the absolute weight of the document can be displayed in digital form on the count display 99. Therefore, the analog signal related to the original weight calculated by the analog adder 95 is converted into a digital signal by the A/D converter 96, passed through the switching circuit B97, and inputted to the display drive circuit 98. The document weight is displayed digitally.

Further, when the output of any one of the load sensors 92 exceeds a certain value and one of the switching circuits A94 is turned off, the warning lamp 100 is turned on, and at the same time, the warning signal is turned on by the gate signal. Therefore, the switching circuit B97 is switched to the weight display side. This switching circuit B97 is normally on the side that passes the copy count display signal to the display drive circuit 98, but only when the gate signal is input, it switches to the weight display side.
As already mentioned, the document weight is digitally displayed on the count display 99. Therefore, by lighting the warning lamp 100 and displaying the document weight, the user can
The user realizes that the original placed on the original table 4 is too heavy.

The count display 99, warning lamp 100, and print switch 101 are arranged on the operation panel 106, as shown in FIG. In FIG. 4, 102 is a slide switch for setting the exposure amount, 103a and 103b are buttons for setting the number of copies, 104 is a jam indicator lamp,
Reference numeral 105 is a lamp indicating that warming up is in progress.

In this embodiment, the warning means for emitting a warning signal when the weight of the document exceeds a predetermined load is configured as described above, and the warning lamp 1
00 is visually displayed, but it is also possible to use an auditory display instead of or together with this.

Further, in this embodiment, the document weight is displayed on the count display 99 only when the warning means is activated, but the document weight is also configured to be displayed as necessary, so that the document weight meter can be used as a so-called document weight meter. It is also possible to make the copying machine equipped with the following.

Furthermore, in this embodiment, when the weight of the document exceeds a predetermined load, the copy restricting means and the warning means are configured to operate simultaneously, but it is also possible to configure such that only one of them operates.

Next, the overall configuration will be explained again. As shown in FIG. 5, the image of the document placed on the document table 4 is
Exposure optical system 7 installed in the body 1 so as to be located under the
The belt-shaped photoreceptor 2 is exposed to light by a slit. The exposure optical system 7 includes a lamp 8 that illuminates the original, a convergent light transmitter 9 that projects the illuminated image of the original onto the belt-shaped photoreceptor 2, and mirrors 10 and 11 that bend the projection optical path.

The lamp 8 has a housing 12 that collects its light in a predetermined position.
The light transmitting member 9 is of a multi-lens type or fiber type and is provided horizontally just above the left end of the belt-like photoreceptor 2. The mirror 10 is provided on the left side of the optical transmission body 9 to guide light from the original to the optical transmission body 9, and the mirror 11 is installed on the right side of the optical transmission body 9 to direct the light exiting the optical transmission body 9 into a belt-shaped photosensitive member. It is designed to lead above the body 2.

The exposure optical system 7 arranged in this way is connected to the belt-shaped photoreceptor 2.
It fits compactly along the right edge and above it. In particular, the bulk on the belt-shaped photoreceptor 2 is reduced.

Further, as shown in FIGS. 5 and 7, a light projecting slit L2a is provided in a portion of the housing 12 facing the belt-shaped photoreceptor 2. As shown in FIG. The light projecting slit 12a is used to directly project the light from the lamp 8 onto the belt-shaped photoreceptor 2 for erasing, thereby omitting the erase means. A shutter 18 is provided in the light projection slit 12a, and the light projection slit 12a is closed at least during image exposure so as not to interfere with image exposure.

For this purpose, as shown in FIG.
．． 41 via springs 42 and 42, and whose central lower edge is fixed to the outer surface of the back side plate inside the fuselage 1.
4 through a wire 43 bent by 90" by a pulley 45. As a result, the shutter 1
8 is held in a balanced state between the solenoid 44 and the pin 41.41, and when the solenoid 44.44 is off, the shutter 18 is pulled up to the upper position by the spring 42 and closes the light emitting slit 12a. , solenoid 4
4 is turned on, it is moved downward against the spring 42 to open the light emitting slit 12a.

A fixing device 13 is provided immediately next to the lamp 8 on the left side of the belt-like photoreceptor 2, and a developing unit 14 is provided immediately next to the right end of the belt-like photoreceptor 2. These fusers 1
3 and the developing unit 14 are formed at approximately the same height, and are lined up along with the belt-shaped photoreceptor 2 approximately horizontally in a straight line. Further, the upper and lower surfaces of the fixing device 13 are along the upper and lower plates of the body 1, and the upper surface of the developing unit 14 is along the upper plate of the body 1. The belt-shaped photoreceptor 2 is stretched to be flatter than the fixing device 13 and the developing unit 14, and has an oblong upper space 15 and a lower space 16 between it and the document table 4 and the bottom of the body 1. and is formed.

The upper space 15 is used as a space for arranging the optical transmission body 9 and mirrors 10 and 11 on both sides thereof.

A charger 17 and a cleaner 51 are disposed in the lower space 16 and are used as a charger and a transfer device while the belt-shaped photoreceptor 2 rotates twice clockwise as shown by the arrow in FIG. ing.

As shown in FIG. 5, the cleaner 51 is located immediately downstream of the developing unit 14 in the direction of rotation of the belt-shaped photoreceptor 2, and is supported by the casing 52 of the developing unit 4.

As shown in FIG. 5, FIG. 8, and FIG. 9, the developing unit 1-14 circulates and conveys the developer while stirring and charging the developer with a developing roller 31 that is close to the belt-shaped photoreceptor 2 with an appropriate gap. A transport roller 33 that supplies developer to the developing roller 31 and a member 32 that supplies toner to the transport roller 33 are provided on the way. As the developing roller 31 rotates, it absorbs the supplied developer and conveys it to a portion facing the belt-shaped photoreceptor 2 . The developer conveyed by the developing roller 31 is further stirred and charged by a magnetic field created by the magnetic poles of a magnet member (not shown) provided in the developing roller 31, and is developed at the portion facing the belt-shaped photoreceptor 2. One opposing magnetic pole serves as a spike of developer. When the spikes of the developer come into contact with the surface of the belt-shaped photoreceptor 2, the toner is electrically attracted to the electrostatic latent image formed on the surface, and the electrostatic latent image is developed.

The developing unit 14 also has a spike of developer formed on the developing roller 31 during non-development and comes into contact with the belt-shaped photoreceptor 2, so that paper dust and the like adhering to the surface of the photoreceptor 2 are removed from the developing unit 14.
The developing roller 31
A developer scraping member 53 is supported by a shaft 50 so as to move toward and away from the developer. As shown in FIGS. 8 and 9, the scraping member 53 connects a shaft 50 and its passive arm 50 to a solenoid 54 attached to the outer surface of the rear end plate of the developing unit 14.
A and a restoring spring 55 is activated. As a result, the scraping member 53 is separated from the developing roller 31 by the bias of the spring 55 while the solenoid 54 is off, and the development by the developing roller 31 is not impaired. When the solenoid 54 is turned on, it is pressed against the developing roller 31 against the bias of the spring 55, scraping off the developer on the developing roller 31, and causing the cleaned peripheral surface of the developing roller to face the belt-shaped photoreceptor 2, so that the developing roller 31 is pressed against the bias of the spring 55. It is possible to prevent the ears from coming into contact with the belt-shaped photoreceptor 2. It is sufficient to scrape off the developer a little after the development unit 14 finishes development.

Note that although the above explanation is for the case where a two-component developer consisting of a magnetic carrier and a toner is used, a -component developer may also be used.

The developing unit 14 can be taken in and out of the machine body 1 along with its casing 52 and a cleaner 51. The cleaner 51 is provided at the tip of a lever 57 that is pivotally supported by a shaft 56.

The lever 57 is pressed against the camshaft 59 by a spring 58 acting on it, and when the camshaft 59 is in the orientation shown in FIG. The photoreceptor 2 is separated from the belt-shaped photoreceptor 2 in response to the urging force of the photoreceptor 2 . This state does not damage the developed image formed on the belt-like photoreceptor 2, and also prevents the cleaner 51 from rubbing against and damaging the belt-like photoreceptor 2 when the developing unit 14 is moved in and out of the machine weight. . The camshaft 59 is the solenoid 6
When the lever 57 is in the direction shown in FIG. 9 due to the ON state of the lever 57, the lever 57 is slightly pushed against the spring 58 from the state shown in FIG. becomes. Note that the solenoid 60 is also attached to the outer surface of the side plate on the inner side of the body l. The toner scraped off by the cleaner 51 falls into a toner receiver 61 formed in a part of the casing 52 and is stored therein. As a result, the developing unit 14 and the cleaner 51 that handle toner can be easily handled as one unit, and problems such as toner spillage are halved.
- Furthermore, cleaning is possible even if the developing unit 4 has the function of a cleaner 51 by temporarily making the potential of the developing bias applied to the developing roller higher than the surface potential of the belt-shaped photoreceptor 2. In this case, as shown in FIG. 5, the cleaner 51 is not required and only the developing unit 14 needs to be provided, so that the apparatus can be further reduced in weight and size.

In the above, the charger 17 serves both as a charger and a transfer device, thereby simplifying the image forming device, and the cleaner 51 cleans the belt-shaped photoreceptor 2 without depending on the developing unit 14, so that cleaning is sufficiently performed. . Moreover, the cleaner 51 is connected to the belt-shaped photoreceptor 2 of the developing unit 14.
It is located immediately downstream in the rotational direction of the belt-shaped photoreceptor 2.
It acts at almost the same position as the developing unit 14, and by switching to the cleaning state immediately after the development by the developing unit 14 is completed, cleaning can be started from the area immediately after the image forming area, and the image forming The time lag between cleaning and cleaning can be almost eliminated.

On the other hand, a paper passing bus 19 for the charger 17 to the transfer section and the fixing section is formed by utilizing the gap between the bottom plate of the body 1 and the bottom surface of the developing unit 14. A transport roller 20 is placed in the middle of this paper passing bus 19 at an appropriate location where it does not interfere with other parts.
21 are provided.

22 indicates a paper feed port, and 23 indicates a paper discharge port.

Next, the copy operation will be explained. First, a document is placed on the document table 4. When the print switch 101 is pressed, the detection of the original weight described above and subsequent processing are performed, and when the original weight is equal to or greater than a predetermined value, the copying operation is stopped. In a normal case, the copy paper is then manually inserted from the paper feed port 22, and when the copy paper turns on the switch 34a, the transport rollers 20, 21 are driven and the manually fed copy paper is fed into the paper path 9. I'll go. Also switch 3
When 4a is turned on, a main motor (not shown) rotates, driving the belt-shaped photoreceptor 2, document table 4, and fixing device 13, and lights up the lamp 8. The first movement of the document table 4 by driving is a continuous movement from the initial position to the scan start position. When the copy paper reaches the switch 34b and turns it on, the transport rollers 20, 21 are turned off, and the copy paper is kept waiting at that position.

Further, when the switch 34b is turned on, the charger 17 is also turned on, and charging of the belt-shaped photoreceptor 2 is started. The shutter 18 is closed before this charging portion reaches the position of the light projection slit 12a.

This allows subsequent exposure without discharging the charged portion.

On the other hand, the direction of movement of the document table 4 is changed from return to scan so that the leading edge of the document is exposed in synchronization with the charged portion of the belt-shaped photoreceptor 2 reaching the exposure position. As a result, the original on the original platen 4 is sequentially exposed to the belt-shaped photoreceptor 2 starting from its leading edge.

Immediately before the leading edge of the exposed portion of the document reaches the developing portion, the developing unit 4 is driven. As a result, when the belt-shaped photoreceptor 2 that has been subjected to the development process comes just before the cleaner 5, the cleaner 51 is separated from the belt-shaped photoreceptor 2.

Next, the conveying rollers 20 and 21 start rotating at the timing when the leading edge of the developed image and the leading edge of the copy paper are aligned.

As a result, the copy paper is brought along the moving belt-shaped photoreceptor 2 so that its developed image coincides with the leading edge of the photoreceptor 2 and reaches the charger 17 . At this time, the charger 17 acts as a transfer charger, and the developed image on the belt-shaped photoreceptor 2 is transferred onto the copy paper.

The copy paper after the transfer is separated from the belt-shaped photoreceptor 2 and passes through, and is fed into the fixing device 13.

Here, the transferred developed image is fixed on the copy paper, and the copy paper is discharged from the paper discharge port 23.

On the other hand, the shutter 18 is opened when the light emitted from the light projector 12a no longer affects the portion of the belt-shaped photoreceptor 2 where the rear end of the document is exposed. As a result, residual charges on the heald-like photoreceptor 2 after the transfer are erased. Further, the cleaner 51 is pressed against the belt-shaped photoreceptor 2 at a predetermined timing after the development of the developing unit 14 is completed to clean it, and the developing roller 31 is moved by the scraping member 5 for a certain period of time after the development is completed.
It is affected by 3.

A time chart of the above main operations is shown in FIG. 10. Utilizing this, each operation timing will be described in more detail based on the movement locus pseudo-diagrams of the image forming start point of the belt-shaped photoreceptor shown in FIGS. 5 and 6.

If the distance that the original platen 4 returns when the switch 34a is turned on is 20 cm, the starting point of the image forming position is a point A, which is 20 cm downstream from the exposure position point P in FIG. Therefore, when the copying start position S of the belt-like photoreceptor 2 at point A reaches the point B, which is the position just upstream of the charger 17 (a position near the point where the copy paper and the belt-like photoreceptor 2 contact), the charger 17 turns on. This ensures that the portions after point S are charged. When the S point of the belt-shaped photoreceptor 2 that has reached this B point further reaches the 0 point, the shutter 1
8 closes. This ensures that the light projected from the light projecting ring 12a does not erase the electrical charge. When the S point goes around and reaches the A point, the developing unit 4 starts operating, and when the S point reaches the D point, the cleaner 5 separates from the bell-shaped photoreceptor 2. When the point S reaches a point E where the leading edge of the copy paper from the transfer section meets the transport rollers 20 and 21, the transport rollers 2o and 21 rotate and begin to transport the copy paper. Thereafter, the developed image is transferred to the copy paper at the transfer position F, and the copy paper is separated from the belt-shaped photoreceptor 2 and moved to the fixing device 13.
Proceed to.

On the other hand, when the S point reaches the 0 point, the shutter 18 opens and erasing starts, and when the S point reaches the A point, the operation of the developing unit 4 ends, and the cleaning starts when the S point reaches the D point. until the copy paper is ejected outside the machine.
The heald-like photoreceptor 2 is driven. Therefore, when point S reaches point G, the main motor stops and everything stops. Of course, it is also possible to stop only the driving of the heald-shaped photoreceptor 2 at the end of the transfer.

In short, at A-B-C-A of the first round in FIG.
The remaining exposure, development, and transfer are performed at A-D-B-C-A of the round, and the copying is completed. Further, as a post-processing of the belt-shaped photoreceptor 2, erasing and cleaning for the entire circumference of the belt-shaped photoreceptor 2 are performed at A-D-B-C-A in the third week.

Note that when the developing unit 14 is not performing development, the developing roller 31
In order to prevent the toner ears of the upper magnetic brush from coming into contact with the heald-like photoreceptor 2, the developing unit 4 itself may be moved backward, in addition to what was described in the above embodiment. Alternatively, the direction of the magnet member may be controlled so that the magnetic pole of the developing roller 31 does not face the belt-shaped photoreceptor 2.

(Effects of the Invention) According to the present invention, when an excessively heavy original is placed on the document table, it is detected and the copying operation is disabled, or the copying operation is stopped based on a warning to that effect. This prevents undue force from acting on the drive system that drives the document table, thereby preventing failure of the drive system, and also prevents the copying machine from tipping over due to unbalance caused by an excessively heavy document. can be prevented from occurring.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing essential parts of an embodiment of the present invention, Fig. 2 is a cross-sectional view thereof, Fig. 3 is a circuit diagram thereof, Fig. 4 is a plan view of the operation panel, and Fig. 5 is a copying machine. A schematic sectional view of the entire structure, FIG. 6 is a pseudo-line diagram of the moving trajectory of the image forming starting point of the belt-shaped photoreceptor, FIG. 7 is a perspective view of the shutter mechanism, and FIGS. 8 and 9 are development units and cleaners. FIG. 10 is a partially enlarged view showing the state during cleaning and the state during cleaning. FIG. 10 is a time chart showing the operation timing of the main equipment.

Claims (1)

[Claims] (1) A copying machine with a movable document table, characterized in that it is equipped with means for detecting the weight of a document, and copying restriction means for disabling a copying operation when the weight of the document exceeds a predetermined load. (2) A copying machine with a movable document table, characterized in that it is equipped with means for detecting the weight of a document, and a warning means for issuing a warning signal when the weight of the document exceeds a predetermined load.