EP0448039B1 - Electrographic image forming apparatus - Google Patents
Electrographic image forming apparatus Download PDFInfo
- Publication number
- EP0448039B1 EP0448039B1 EP19910104237 EP91104237A EP0448039B1 EP 0448039 B1 EP0448039 B1 EP 0448039B1 EP 19910104237 EP19910104237 EP 19910104237 EP 91104237 A EP91104237 A EP 91104237A EP 0448039 B1 EP0448039 B1 EP 0448039B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- developer
- toner
- units
- attached
- toner density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 108091008695 photoreceptors Proteins 0.000 claims description 11
- 238000001514 detection method Methods 0.000 claims description 7
- 238000004088 simulation Methods 0.000 claims description 4
- 230000004044 response Effects 0.000 claims description 2
- 238000012937 correction Methods 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 239000003086 colorant Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000007257 malfunction Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0896—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
- G03G15/0105—Details of unit
- G03G15/0126—Details of unit using a solid developer
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
- G03G15/0848—Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
- G03G15/0849—Detection or control means for the developer concentration
Definitions
- the present invention relates to an image forming apparatus according to the preamble of the independent claim 1.
- Such an apparatus is known from US-4 885 611.
- the apparatus may be an electrographic copying machine and a printer, etc. More particularly, the present invention relates to an image forming apparatus with a toner density controller.
- electrographic copying machines have been used in which a latent image formed on the photoreceptor is developed by using plural different colors of toner as well as one color of toner.
- a main developer unit and a sub developer unit are arranged with respect to the periphery of the photoreceptor drum, and these developer units are selectively activated.
- a toner density controlling mechanism is provided in electrographic copying machines to maintain the toner density at a fixed level.
- a toner density sensor is provided on each developer unit, and the toner density detected by the toner density sensor is compared with the predetermined toner density by a microcomputer. Then, by controlling the toner supply with a toner supply roller in response to the control signal out-putted according to the above comparison, toner density is maintained at an appropriate fixed level.
- the initial value is used as the reference value. The difference between the detected toner density and the reference value is calculated to control toner supply.
- the initial value is the ratio T/D of toner to carrier in the initial condition
- the detected toner density is also the ratio of toner to carrier.
- Correction data for the output of the toner density sensor are prepared in consideration of the influence of a magnet roller in a developer sleeve, also called "developer shell", of the developer unit since it is affected by the magnet roller.
- the correction which is based on the data, is not accurately performed since the toner density sensor of the other developer unit is not affected by the magnet roller of the above detached developer unit.
- US-4 885 611 discloses a multicolor image forming apparatus. It is equipped with a plurality of developing units respectively using different color toners. Forming of two color images is inhibitted and an alarm signal is provided, when only one of the plurality of developing units is mounted in place on the frame of the image forming apparatus.
- FR-A-2 596 536 discloses an image forming apparatus.
- a developer unit comprises a toner density detector at the point of agitating the toner. Output signals of this detector are used for producing appropriate displays for a user.
- the dependent claim is directed on a preferred embodiment of the invention.
- control means in the image forming apparatus have a function to control the initial setting of the developer in each developer unit so that the setting is performed only when a predetermined plural number of developer units are attached to the image forming apparatus body in the simulation mode.
- Fig. 1 is a composition diagram of an electrographic copying machine as an embodiment of the present invention that copies originals in plural colors.
- Fig. 2 is an enlarged cross-sectional view of the developer units shown in Fig. 1.
- Fig. 3 is a block circuit diagram of the principal section of the image forming apparatus shown in Fig. 1.
- Fig. 4 is a circuit composition diagram of the dip switch shown in Fig. 3.
- Fig. 5 is an external perspective view of a sub developer unit in which the dip switch is provided.
- Fig. 1 the image of an original 6 placed on a contact glass 4, pressed by an original cover 5, is scanned by a scan optical system 7.
- the image information is transmitted on light via condenser lens 8 to a light receiving element 9 such as CCD (Charge Coupled Device).
- a light receiving element 9 such as CCD (Charge Coupled Device).
- CCD Charge Coupled Device
- the image information is formed into a latent image on a photoreceptor drum 1 by a laser scanner unit 11.
- the surface of the photoreceptor drum 1 is charged by a main charger 100.
- the latent image on the photoreceptor drum 1 is developed by a main developer unit 2 or a sub developer unit 3 and is transferred to a paper at transfer position 13.
- Fig. 1, 14 is a bypass table for feeding paper
- 15 is an upper paper feed cassette
- 16 is a lower paper feed cassette
- 17 and 18 are paper feed rollers
- 19 is a conveying roller
- 20 is a resisting roller
- 21 is a transferring charger
- 22 is a separating charger.
- the paper to which an image on the drum 1 is transferred is conveyed to a fixing unit 24 by a conveying belt 23. After fixed at the fixing unit 24, the paper is discharged on a discharge tray 26 through discharge rollers 25.
- the paper fixed at the fixing unit 24 can be led to a middle tray 28 through reverser 27 to be ready for the re-transferring of the image on the drum 1.
- the main developer unit 2 contains black toner to form black images.
- the sub developer unit 3 contains toner of another color to form images of another color.
- the developer units 2 and 3 can separately be attached to or detached from a copying machine body.
- Fig. 2 is a cross-sectional view showing the details of the developer units 2 and 3.
- the structure of only main developer unit 2 is described since the main developer unit 2 and the sub developer unit 3 have the same structure and they are different only in that they contain different colors of toner and that the sub developer unit 3 is smaller than the main developer unit 2.
- a developer 33 consisting of toner and carrier is supplied to the developer shell 30 after stirred by a paddle 32 that rotates on the axis parallel to that of the developer shell 30 and on which fins 31 are radially provided.
- the developer shell 30 is attached on the periphery of the magnet roller 34, and the toner on the developer shell 30 is provided to the surface of the photoreceptor drum 1 through the developer shell 30.
- the toner density of the developer 33 is detected by the toner density sensor 35, and the detected value and a predetermined reference value are compared at a control section 40 that comprises a microcomputer shown in Fig. 3.
- the control section 40 operates based on the program stored in a ROM42.
- the control section 40 A/D(analog-to-digital)-converts the toner density detection signal generated by the toner density sensor 35 of the main developer unit 2, and after comparing the detected value with the reference value pre-memorised in RAM43, outputs a control signal.
- the control section 40 controls the toner supply roller driving motor so that the toner supply decreases, and when the detection value is smaller than the reference value, it controls the toner supply roller driving motor so that the toner supply increases.
- control section 40 controls the toner supply in the same manner to maintain the toner density of the sub developer unit 3 at a fixed level.
- control section 40 performs the above-described toner density control operation, the copying operation and an initial setting of developer.
- the control section 40 does not perform the above operations. Therefore, it is necessary to detect whether the developer units 2 and 3 are attached or not. The detection is performed as hereinafter described.
- the main developer unit 2 is judged to be attached when the toner density sensor 35 outputs voltage data of 0V to 5V.
- the toner density sensor 35 does not output voltage data of nearly 0V since the main developer unit 2 contains approximately 1kg of developer and never becomes vacant. If it should become nearly vacant, the voltage of, for example, 2V or 3V is normally outputted.
- whether the sub developer unit 3 is attached or not is judged by using the output of a dip switch 47 instead of that of the toner density sensor 37. Since the entire body of the sub developer unit 3 is smaller than that of the main developer unit 2 and, normally, only approximately 200g of developer is contained in the sub developer unit 3, the output of the toner density sensor 37 is unstable and sometimes reaches nearly 0V.
- the sub developer unit 3 generally comprises a dip switch 47 with a circuit composition as shown in Fig. 4 for indicating the color of the toner the sub developer unit 3 contains.
- the color of the toner is identified by detecting the setting condition of the dip switch 47.
- the color is identified by setting the dip switch 47 in the conditions (a), (b) or (c) shown in Fig. 4, where, for example, the color of the toner is red when the switch is set in the condition (a), blue, in the condition (b), and green, in the condition (c).
- the dip switch 47 is attached to the sub developer unit 3 as shown in Fig. 5, and is set as described above by rotating its rotation driving portion 48 with, for example, a screwdriver. By detecting the output of the dip switch 47, whether the sub developer unit 3 is attached or not is detected.
- the terminals T1 to T4 shown in Fig. 4 are connected to a circuit provided in the copying machine body, and the control section 40 judges which of the terminals T1 to T3 is connected to the terminal T4 through the dip switch 47.
- the above judgment by the control section 40 is an identification of the color of the toner. However, it represents the sub developer unit 3 is attached to the copying machine body that the above judgment can be performed. Therefore, the control section 40 detects whether the developer units are attached or not based on the above judgment.
- the detection of whether the main developer unit 2 and the sub developer unit 3 are attached or not is not necessarily performed in the above-described manner; it can be performed in other appropriate manners. For example, the detection can be also performed by providing a switch which is turned on or off when a developer unit is attached to a copying machine body, on a developer unit attaching section of the copying machine body, so that the control section 40 can perform the judgment with the output of the switch.
- the control section 40 detects whether the main and sub developer units 2 and 3 are attached or not in the above-described manner.
- the control section 40 makes a copying mechanism section 46 operationable when both of the main and sub developer units 2 and 3 are attached; when either of the developer units is not attached, it makes the copying mechanism section 46 unoperationable.
- the toner density control is performed only when a predetermined plural number of developer units are attached to an image forming apparatus body and the output data of the developer units are required to be corrected only when the developer units are attached, malfunction of the correction is not generated.
- the initial value can be set in the condition where either of the developer units is attached or where both of the developer units are attached. Even when only one of the developer units is attached, correct data may be chosen in the correction of the toner density of both the developer units 2 and 3, since it is clear that, in the copying operation, the toner density control is performed only when both of the developer units are attached.
- the above-described is an embodiment when two developer units are provided.
- the same method is applicable to the copying machine with which three or more developer units are provided.
- the copying machine can be so constructed that the copying operation and the initial setting are operationable when predetermined plural number of developer units are attached as well as when all of them are attached.
- the above embodiment is an application of the present invention to a copying machine.
- the present invention is also applicable to a printer.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dry Development In Electrophotography (AREA)
- Color Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Description
- The present invention relates to an image forming apparatus according to the preamble of the
independent claim 1. Such an apparatus is known from US-4 885 611. The apparatus may be an electrographic copying machine and a printer, etc. More particularly, the present invention relates to an image forming apparatus with a toner density controller. - Recently, electrographic copying machines have been used in which a latent image formed on the photoreceptor is developed by using plural different colors of toner as well as one color of toner. In such electrographic copying machines, a main developer unit and a sub developer unit are arranged with respect to the periphery of the photoreceptor drum, and these developer units are selectively activated.
- Since the toner density changes as the developer units are used, a toner density controlling mechanism is provided in electrographic copying machines to maintain the toner density at a fixed level. To detect toner density, a toner density sensor is provided on each developer unit, and the toner density detected by the toner density sensor is compared with the predetermined toner density by a microcomputer. Then, by controlling the toner supply with a toner supply roller in response to the control signal out-putted according to the above comparison, toner density is maintained at an appropriate fixed level. Generally, in a toner density control, the initial value is used as the reference value. The difference between the detected toner density and the reference value is calculated to control toner supply. The initial value is the ratio T/D of toner to carrier in the initial condition, and the detected toner density is also the ratio of toner to carrier. Correction data for the output of the toner density sensor are prepared in consideration of the influence of a magnet roller in a developer sleeve, also called "developer shell", of the developer unit since it is affected by the magnet roller. In a case where the initial value of each of main and sub developer units attached to the copying machine is detected and a copying operation is performed after detaching one of the developer units, the correction, which is based on the data, is not accurately performed since the toner density sensor of the other developer unit is not affected by the magnet roller of the above detached developer unit. Moreover, when correction data for the output of the toner density sensor are prepared in the condition where the initial value of each developer unit is predetermined without considering the influence of the other developer unit and where the two developer units are attached, if the copying operation is performed with one developer unit and the output of the toner density sensor is corrected in accordance with the prepared data, the same problem is arisen.
- US-4 885 611 discloses a multicolor image forming apparatus. It is equipped with a plurality of developing units respectively using different color toners. Forming of two color images is inhibitted and an alarm signal is provided, when only one of the plurality of developing units is mounted in place on the frame of the image forming apparatus.
- FR-A-2 596 536 discloses an image forming apparatus. A developer unit comprises a toner density detector at the point of agitating the toner. Output signals of this detector are used for producing appropriate displays for a user.
- It is the object of the present invention to provide a simple detecting mechanism for a plurality of developer units and to perform a correct toner density control.
- This object is solved in accordance with the features of the
independent claim 1. The dependent claim is directed on a preferred embodiment of the invention. - In the above structure, malfunction of the correction is not generated, since the toner density control is performed only when a predetermined plural number of developer units are attached to an image forming apparatus body, and the output of the developer units are required to be corrected only when the developer units are attached. In other word, the output of the toner density sensor does not change according to the number of the attached developer unit.
- Moreover, the control means in the image forming apparatus have a function to control the initial setting of the developer in each developer unit so that the setting is performed only when a predetermined plural number of developer units are attached to the image forming apparatus body in the simulation mode.
- With such control means, it is unnecessary to correct the toner density data since the output change of the toner density sensor in the initial setting is the same as that in the copying operation, and the structures of both the hardware and software are made simple.
- These and other objects and features of this invention will become clear from the following description taken in conjunction with the preferred embodiments with reference to the accompanied drawings in which:
- Fig. 1 is a composition diagram of an electrographic copying machine as an embodiment of the present invention that copies originals in plural colors.
- Fig. 2 is an enlarged cross-sectional view of the developer units shown in Fig. 1.
- Fig. 3 is a block circuit diagram of the principal section of the image forming apparatus shown in Fig. 1.
- Fig. 4 is a circuit composition diagram of the dip switch shown in Fig. 3.
- Fig. 5 is an external perspective view of a sub developer unit in which the dip switch is provided.
- The present invention will hereinafter be explained with reference to the accompanying drawings. In Fig. 1, the image of an original 6 placed on a
contact glass 4, pressed by anoriginal cover 5, is scanned by a scanoptical system 7. The image information is transmitted on light viacondenser lens 8 to a light receivingelement 9 such as CCD (Charge Coupled Device). After converted into an electric signal at the light receivingelement 9, it is processed in an imageinformation processing circuit 10. Then, the image information is formed into a latent image on aphotoreceptor drum 1 by alaser scanner unit 11. Before the latent image is formed, the surface of thephotoreceptor drum 1 is charged by amain charger 100. The latent image on thephotoreceptor drum 1 is developed by amain developer unit 2 or asub developer unit 3 and is transferred to a paper attransfer position 13. In Fig. 1, 14 is a bypass table for feeding paper, 15 is an upper paper feed cassette, 16 is a lower paper feed cassette, 17 and 18 are paper feed rollers, 19 is a conveying roller, 20 is a resisting roller, 21 is a transferring charger, and 22 is a separating charger. The paper to which an image on thedrum 1 is transferred is conveyed to afixing unit 24 by aconveying belt 23. After fixed at thefixing unit 24, the paper is discharged on adischarge tray 26 throughdischarge rollers 25. The paper fixed at thefixing unit 24 can be led to amiddle tray 28 throughreverser 27 to be ready for the re-transferring of the image on thedrum 1. Themain developer unit 2 contains black toner to form black images. Thesub developer unit 3 contains toner of another color to form images of another color. Thedeveloper units - Fig. 2 is a cross-sectional view showing the details of the
developer units main developer unit 2 is described since themain developer unit 2 and thesub developer unit 3 have the same structure and they are different only in that they contain different colors of toner and that thesub developer unit 3 is smaller than themain developer unit 2. First, adeveloper 33 consisting of toner and carrier is supplied to thedeveloper shell 30 after stirred by apaddle 32 that rotates on the axis parallel to that of thedeveloper shell 30 and on whichfins 31 are radially provided. Thedeveloper shell 30 is attached on the periphery of themagnet roller 34, and the toner on thedeveloper shell 30 is provided to the surface of thephotoreceptor drum 1 through thedeveloper shell 30. In this process, the toner density of thedeveloper 33 is detected by thetoner density sensor 35, and the detected value and a predetermined reference value are compared at acontrol section 40 that comprises a microcomputer shown in Fig. 3. - The
control section 40 operates based on the program stored in a ROM42. In the black-and-white image forming mode in which themain developer unit 2 operates, the control section 40 A/D(analog-to-digital)-converts the toner density detection signal generated by thetoner density sensor 35 of themain developer unit 2, and after comparing the detected value with the reference value pre-memorised in RAM43, outputs a control signal. At this time, to maintain the toner density of themain developer unit 2 at a fixed level, when the detected value is larger than the reference value, thecontrol section 40 controls the toner supply roller driving motor so that the toner supply decreases, and when the detection value is smaller than the reference value, it controls the toner supply roller driving motor so that the toner supply increases. In the color image forming mode in which thesub developer unit 3 operates, thecontrol section 40 controls the toner supply in the same manner to maintain the toner density of thesub developer unit 3 at a fixed level. However, it is only when both of the main andsub developer units control section 40 performs the above-described toner density control operation, the copying operation and an initial setting of developer. When either of the developer units is detached, thecontrol section 40 does not perform the above operations. Therefore, it is necessary to detect whether thedeveloper units - First, the
main developer unit 2 is judged to be attached when thetoner density sensor 35 outputs voltage data of 0V to 5V. At this time, generally, thetoner density sensor 35 does not output voltage data of nearly 0V since themain developer unit 2 contains approximately 1kg of developer and never becomes vacant. If it should become nearly vacant, the voltage of, for example, 2V or 3V is normally outputted. On the other hand, whether thesub developer unit 3 is attached or not is judged by using the output of adip switch 47 instead of that of thetoner density sensor 37. Since the entire body of thesub developer unit 3 is smaller than that of themain developer unit 2 and, normally, only approximately 200g of developer is contained in thesub developer unit 3, the output of thetoner density sensor 37 is unstable and sometimes reaches nearly 0V. Therefore, whether thesub developer unit 3 is attached or not cannot be judged by the output of thetoner density sensor 37. Thesub developer unit 3 generally comprises adip switch 47 with a circuit composition as shown in Fig. 4 for indicating the color of the toner thesub developer unit 3 contains. The color of the toner is identified by detecting the setting condition of thedip switch 47. For example, the color is identified by setting thedip switch 47 in the conditions (a), (b) or (c) shown in Fig. 4, where, for example, the color of the toner is red when the switch is set in the condition (a), blue, in the condition (b), and green, in the condition (c). - The
dip switch 47 is attached to thesub developer unit 3 as shown in Fig. 5, and is set as described above by rotating itsrotation driving portion 48 with, for example, a screwdriver. By detecting the output of thedip switch 47, whether thesub developer unit 3 is attached or not is detected. When thesub developer unit 3 is attached to a copying machine body, the terminals T1 to T4 shown in Fig. 4 are connected to a circuit provided in the copying machine body, and thecontrol section 40 judges which of the terminals T1 to T3 is connected to the terminal T4 through thedip switch 47. - The above judgment by the
control section 40 is an identification of the color of the toner. However, it represents thesub developer unit 3 is attached to the copying machine body that the above judgment can be performed. Therefore, thecontrol section 40 detects whether the developer units are attached or not based on the above judgment. The detection of whether themain developer unit 2 and thesub developer unit 3 are attached or not is not necessarily performed in the above-described manner; it can be performed in other appropriate manners. For example, the detection can be also performed by providing a switch which is turned on or off when a developer unit is attached to a copying machine body, on a developer unit attaching section of the copying machine body, so that thecontrol section 40 can perform the judgment with the output of the switch. - The
control section 40 detects whether the main andsub developer units control section 40 makes acopying mechanism section 46 operationable when both of the main andsub developer units copying mechanism section 46 unoperationable. - Since the toner density control is performed only when a predetermined plural number of developer units are attached to an image forming apparatus body and the output data of the developer units are required to be corrected only when the developer units are attached, malfunction of the correction is not generated.
- In the simulation mode, the initial value can be set in the condition where either of the developer units is attached or where both of the developer units are attached. Even when only one of the developer units is attached, correct data may be chosen in the correction of the toner density of both the
developer units - Moreover, in the simulation mode, it is possible to make the initial setting of the developer unoperationable when only one of the developer units is attached. In this case, it is not necessary to correct the toner density data since the output change of the
toner density sensors - The above-described is an embodiment when two developer units are provided. The same method is applicable to the copying machine with which three or more developer units are provided. Moreover, when three or more developer units are provided, the copying machine can be so constructed that the copying operation and the initial setting are operationable when predetermined plural number of developer units are attached as well as when all of them are attached. The above embodiment is an application of the present invention to a copying machine. The present invention is also applicable to a printer.
- Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.
Claims (2)
- An electrographic image forming apparatus comprising:
a photoreceptor (1);
plural developer units (2, 3) for giving toner alternatively to said photoreceptor (1) to develop a latent image formed on said photoreceptor (1), respectively comprising a developing sleeve (30, 38) attached on a magnet roller (34, 39), and which are separately attachable and detachable with respect to the periphery of said photoreceptor (1), and respectively containing developer comprising toner and carrier, and said plural developer units (2, 3) further comprise a main developer unit (2) for forming an image of a particular color and a sub-developer unit (3) having a smaller developer container for forming an image of another color,
toner supply means (31, 36) for supplying toner to said plural developer units (2, 3);
detection means (35, 40, 47) for detecting whether said plural developer units are attached with respect to said periphery of said photoreceptor (1); and
control means (40) for so controlling the image forming operation as to be performed only when all of said plural developer units (2, 3) are attached,
characterized in that
each of said plural developer units (2, 3) comprises a toner density sensor (35, 37) for sensing the ratio of toner to carrier, said toner supply means (31, 36) supplying toner according to the difference between an output of said toner density sensor (35, 37) and a reference value, and said detection means (35, 40, 47) detects an attachment of said main developer unit (2) in response to the presence of said output of said toner density sensor (35) of said main developer unit (2), and an attachment of said sub-developer unit (3) according to an output of a color identifying switch (47) that indicates the color of the toner in said sub-developer unit (3). - An electrographic image forming apparatus according to claim 1,
characterized in that
said control means (40) contains and operates in a simulation mode to control an initial setting of said toner density reference value of the developer of each of said plural developer units (2, 3) so that said setting is performed only when all of said plural developer units (2, 3) are attached.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP68765/90 | 1990-03-19 | ||
JP2068765A JPH03267968A (en) | 1990-03-19 | 1990-03-19 | Image forming device |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0448039A2 EP0448039A2 (en) | 1991-09-25 |
EP0448039A3 EP0448039A3 (en) | 1992-12-02 |
EP0448039B1 true EP0448039B1 (en) | 1995-11-15 |
Family
ID=13383160
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19910104237 Expired - Lifetime EP0448039B1 (en) | 1990-03-19 | 1991-03-19 | Electrographic image forming apparatus |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0448039B1 (en) |
JP (1) | JPH03267968A (en) |
DE (1) | DE69114556T2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7136831B2 (en) * | 2001-04-27 | 2006-11-14 | Canon Kabushiki Kaisha | Collection information management server and collection information management method |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60164776A (en) * | 1984-02-08 | 1985-08-27 | Hitachi Ltd | Developing device |
JPH0679171B2 (en) * | 1984-12-26 | 1994-10-05 | キヤノン株式会社 | Image forming device |
DE3704993A1 (en) * | 1986-03-31 | 1987-10-08 | Toshiba Kk | IMAGE GENERATION DEVICE |
JPS6385771A (en) * | 1986-09-30 | 1988-04-16 | Mita Ind Co Ltd | Copying device |
JPS63155062A (en) * | 1986-12-19 | 1988-06-28 | Toshiba Corp | Image forming device |
JPH0682244B2 (en) * | 1987-08-03 | 1994-10-19 | キヤノン株式会社 | Process cartridge and image forming apparatus |
JPS63206774A (en) * | 1987-02-24 | 1988-08-26 | Minolta Camera Co Ltd | Image forming device |
JPS63208871A (en) * | 1987-02-26 | 1988-08-30 | Minolta Camera Co Ltd | Image forming device |
JPH0820841B2 (en) * | 1987-03-03 | 1996-03-04 | 三田工業株式会社 | Mounting detection device for process unit |
US4897690A (en) * | 1987-09-30 | 1990-01-30 | Minolta Camera Kabushiki Kaisha | Image forming apparatus |
JP2564871B2 (en) * | 1988-01-13 | 1996-12-18 | ミノルタ株式会社 | Optional toner replenisher for image forming device |
JPH0266582A (en) * | 1988-08-31 | 1990-03-06 | Mita Ind Co Ltd | Multiple color developing device for image forming device |
-
1990
- 1990-03-19 JP JP2068765A patent/JPH03267968A/en active Pending
-
1991
- 1991-03-19 EP EP19910104237 patent/EP0448039B1/en not_active Expired - Lifetime
- 1991-03-19 DE DE1991614556 patent/DE69114556T2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH03267968A (en) | 1991-11-28 |
EP0448039A2 (en) | 1991-09-25 |
DE69114556T2 (en) | 1996-04-11 |
DE69114556D1 (en) | 1995-12-21 |
EP0448039A3 (en) | 1992-12-02 |
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