Image forming apparatus and storage

Abstract

To manage information on a loaded component loaded in an apparatus by using a fuse, while minimizing the number of signal lines between the loaded component and an apparatus body.SOLUTION: The present invention relates to an image forming apparatus loaded with a storage and a fuser having the storage. The storage of the present invention has a storage element, contacts between a control unit and the storage element, and Zener diodes and a fuse connected in series and arranged between the contacts and grounds. An image forming apparatus body of the present invention controls the storage element with an electric signal equal to or less than Zener voltage when accessing the storage element, applies, to the contacts, voltage at which the fuse is not cut when checking the state of the fuse to determine the state of the fuse according to a voltage level based on the voltage at the contacts, and applies, to the contacts, voltage at which the fuse is cut through the Zener diodes when cutting the fuse.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus and a storage device, and can be applied, for example, to a printing apparatus (printer) equipped with consumables such as a fixing device that fixes a toner image transferred to a medium. [Background technology]

[0002] Conventionally, an image forming apparatus equipped with consumables such as a fixing unit is disclosed in Patent Document 1. Patent Document 1 describes that a fuse for recording a flag related to management of a consumable used in an image forming apparatus is provided inside the consumable. The image forming apparatus described in Patent Document 1 has a means for blowing (disconnecting) a fuse (a fuse that is not blown) by passing a first current through a terminal (signal line) connected to the fuse included in the consumable, and a means for detecting the state of the fuse (whether it is blown or not) by passing a second current (first current>second current) that is not strong enough to blow the fuse through a terminal (signal line) connected to the fuse. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-021991 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in a conventional image forming device, if a fuse as described in Patent Document 1 is installed in a consumable and managed, it is necessary to secure at least two signal lines (signal lines required for the circuit to pass current through the fuse) between the image forming device main body and each fuse. However, it is desirable to use fuses to manage management information related to the fixing unit, without increasing the number of signal lines between the image forming device main body and the fixing unit as much as possible.

[0005] In view of the above problems, it is desirable to be able to use fuses to manage information about components mounted on an apparatus (e.g., a fixing unit mounted on an image forming apparatus; hereinafter referred to as "mounted components") without increasing the number of signal lines between the apparatus (e.g., image forming apparatus) body as much as possible. [Means for solving the problem]

[0006] The first invention is an image forming apparatus including a fixing unit for fixing a developer image on a medium and a control unit, wherein the fixing unit has a memory element capable of recording data, a contact between the control unit and the memory element, and a memory device in which a Zener diode having a Zener voltage as a first voltage and a fuse are connected in series and arranged between the contact and ground, the control unit has a voltage level detection means for detecting a voltage level based on the voltage of the contact, and when accessing the memory element via the contact, the control unit controls the memory element with an electrical signal that is equal to or lower than the first voltage, when checking the state of the fuse, the control unit applies to the contact a second voltage that is equal to or higher than the first voltage and does not blow the fuse, and determines the state of the fuse according to the voltage level detected by the voltage level detection means, and when blowing the fuse, the control unit applies to the contact a third voltage that blows the fuse via the Zener diode.

[0007] The second invention is characterized in that a memory device included in an on-board component mounted on an apparatus has a memory element capable of recording data, a contact between a main body of the apparatus and the memory element, a Zener diode having a Zener voltage as a first voltage, and a fuse connected in series with the Zener diode, the Zener diode and the fuse being arranged between the contact and ground. Effect of the Invention

[0008] According to the present invention, it is possible to use fuses to manage information about mounted components without increasing the number of signal lines between the mounted components mounted on the device and the device body. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a block diagram showing the functional configuration of a printing apparatus according to an embodiment. [Diagram 2] 2 is a diagram showing a detailed configuration of an image forming processing section and a fixing unit that constitute a mechanical section according to the embodiment; FIG. [Diagram 3] 1 is a diagram (circuit diagram) showing a detailed configuration of a memory circuit and a memory control circuit according to an embodiment; [Figure 4] 4 is a diagram (perspective view of the fixing unit) showing an example of a mounting structure of a memory circuit in the fixing unit according to the embodiment; FIG. [Diagram 5] FIG. 2 is an enlarged schematic diagram of a tag board according to an embodiment; [Figure 6] 11A and 11B are diagrams showing patterns of switching states of a switching circuit and a power supply voltage level in a memory control circuit according to an embodiment. [Figure 7] 11 is a diagram showing detection voltage levels for each combination of fuse states and contact states according to an embodiment. FIG. [Figure 8] 11 is a flowchart showing an example of a process in which a control processing unit according to the embodiment checks a high temperature error flag at start-up. [Figure 9] 10 is a flowchart showing an operation performed when a control processing unit according to the embodiment detects a high temperature error in the fixing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (A) Main embodiment An embodiment of an image forming apparatus according to the present invention will be described below in detail with reference to the drawings. In this embodiment, an example will be described in which the image forming apparatus of the present invention is applied to a printing apparatus (printer), and the memory device of the present invention is applied to a memory circuit mounted in a fixing device of the printing apparatus.

[0011] (A-1) Configuration of the embodiment FIG. 1 is a block diagram showing the functional configuration of a printing device 1 according to this embodiment.

[0012] As shown in FIG. 1, the printing device 1 functionally comprises at least a control unit 2, a communication unit 3, a display unit 4, and an image forming unit 5.

[0013] The communication unit 3 functions as an interface (network interface) for communicating with an external device via a network.

[0014] The control unit 2 is responsible for the overall control function of the printing device 1. The control unit 2 performs various control processes for the image forming unit 5. The printing device 1 analyzes print data transmitted from a higher-level device (for example, a host computer such as a PC) using the communication unit 3, generates raster data (data for drawing), and instructs the image forming unit 5 to print (form an image) based on the generated raster data.

[0015] The display unit 4 has a function of displaying images (for example, images of characters, figures, etc.) according to the control of the control unit 2. As the display unit 4, for example, various displays and the like can be applied.

[0016] The image forming unit 5 has the function of forming (printing) an image on a medium (e.g., printing paper) according to instructions from the control unit 2. In this embodiment, the image forming unit 5 is equipped with a mechanism unit 6 that performs electrophotographic image formation (printing). The mechanism unit 6 is broadly divided into an image formation processing unit 7 that develops a toner image (developer image) using toner (developer) according to instructions from the control unit 2 and transfers it to printing paper (medium), and a fixing device 8 that applies heat and pressure to the printing paper to which the toner image has been transferred, thereby fixing the toner image to the medium.

[0017] The fixing unit 8 is equipped with a memory circuit 9 as a means (a memory device in this embodiment) for recording various information such as management information, etc. The memory circuit 9 will be described in detail later.

[0018] Next, the configuration of the mechanism section 6 constituting the image forming section 5 will be described with reference to FIG.

[0019] FIG. 2 is a diagram showing a detailed configuration (schematic side view) of the image forming processing section 7 and the fixing unit 8 that constitute the mechanical section 6. As shown in FIG.

[0020] The image forming processing section 7 develops a toner image (developer image) and transfers it to a printing paper M as a printing medium (image forming medium), and includes four LED heads 110 (110-1 to 110-4), four image drum units 117 (117-1 to 117-4), four transfer devices 114 (114-1 to 114-4), and a transfer belt 116. The image drum units 117-1 to 117-4 are respectively equipped with toner (developer) of yellow, magenta, cyan, and black, and are means (developing means) for developing a toner image (developer image) using the toner equipped therein. The printing paper M is fed from a paper feeder (not shown) in the mechanism section 6. In addition to the above, the mechanism section 6 also includes rollers for feeding paper (not shown). The number (number of channels) of the image drum units 117 / LED heads 110 mounted in the image forming processing section 7 is not limited to the above example.

[0021] Each of image drum units 117-1 to 117-4 has developer 111, charger 112, and photosensitive unit 115. LED heads 110-1 to 110-4 are exposure means for exposing photosensitive unit 115 of image drum units 117-1 to 117-4 to form an electrostatic latent image, and are configured with a plurality of light-emitting elements arranged in the main scanning direction. Charger 112 is a means for uniformly charging the surface of photosensitive unit 115. LED heads 110-1 to 110-4 are a means for selectively exposing the uniformly charged surface of photosensitive unit 115 to light to form an electrostatic latent image. Developer 111 is a means for attaching toner (developer of a corresponding color) to the electrostatic latent image formed on the surface of photosensitive unit 115 to develop a toner image (developer image). Transfer belt 116 is a means for transporting print paper M between image drum units 117-1 to 117-4 and transfer devices 114-1 to 114-4. Transfer devices 114-1 to 114-4 are means for transferring toner images developed on opposing image drum units 117-1 to 117-4 (photosensitive units 115) onto print paper M transported by transfer belt 116.

[0022] The fixing device 8 is a fixing means that fixes the toner image transferred to the print paper M by heat and pressure. In the mechanism section 6, an entrance sensor 113 that detects (optically detects) the print paper M is disposed at the entrance of the fixing device 8. When the print paper M enters the fixing device 8, the entrance sensor 113 outputs a signal indicating that the paper is passing. The print paper M that has entered the fixing device 8 is subjected to heat and pressure as it passes between the two heat rollers 152, 153. The fixing device 8 is equipped with a heater 170 as a heat source and a thermistor 171 as a temperature detection means.

[0023] The image formation processing section 7 (mechanism section 6) has the above-mentioned configuration. Next, an overview of the print process (image formation process) in the image formation processing section 7 (mechanism section 6) will be described.

[0024] When print data is supplied from a higher-level device, control unit 2 edits the image data, operates image forming processing unit 7 (mechanism unit 6), and transmits the image data to LED heads 110-1 to 110-4. LED heads 110-1 to 110-4 blink dots (LEDs) designated by the image data, and form electrostatic latent images on opposing image drum units 117-1 to 117-4 (photosensitive units 115). In each of image drum units 117-1 to 117-4, toner is supplied to photosensitive unit 115 by developing unit 111, and a toner image based on the electrostatic latent image is formed. The toner images formed on image drum units 117-1 to 117-4 (photosensitive units 115) are attracted to the printing paper M side by a high voltage (Coulomb force) applied by transfer units 114-1 to 114-4 facing the back side of printing paper M. Through the above-described process, the image forming processing unit 7 (mechanism unit 6) transfers (adsorbs) the toner image onto the print medium M. Then, in the image forming processing unit 7 (mechanism unit 6), when the print medium M onto which the toner image has been transferred is transported to the fixing device 8, the toner image is fixed onto the print medium M.

[0025] Next, the internal configuration of the memory circuit 9 included in the fixing unit 8 and the control unit 2 included in the main body of the printing device 1 will be described.

[0026] 1, the control unit 2 has a control processing unit 10 that performs control processing for each unit including the fixing unit 8, and a storage control circuit 11 that controls the storage circuit 9 under the control of the control processing unit 10. In other words, the control processing unit 10 controls (accesses) the storage circuit 9 via the storage control circuit 11.

[0027] As shown in FIG. 1, the memory circuit 9 includes a memory element 304 and a fuse 301 as a data recording medium (hereinafter referred to as a "management information recording medium") capable of recording various information such as management information for the fixing unit 8.

[0028] The storage element 304 is an element (for example, a semiconductor element such as an IC chip) that functions as a memory (non-volatile memory) capable of reading and writing data including management information for the fixing unit 8.

[0029] The fuse 301 melts (cuts) when a current of a predetermined level or more flows. The specifications of the fuse 301 (for example, conditions under which melting occurs, etc.) are not limited, and various conditions can be set. Although the items of management information applied to the fuse 301 are not limited, in this embodiment, an example will be described in which the fuse 301 is used as a flag (hereinafter referred to as a "high temperature error flag") for determining whether or not a high temperature error (for example, an error that occurs when the temperature detected by the thermistor 171 or the like becomes a predetermined level or higher) has occurred in the fixing unit 8. Here, it is assumed that a fixing unit 8 that has experienced a high temperature error even once is in danger of safety and therefore needs to be prevented from being reused. The fuse 301 may be applied to other items of management information (for example, a flag for determining whether the fuser 301 is new or old, a flag for managing the lifespan, etc.).

[0030] In this embodiment, it is assumed that data of the high temperature error flag can also be recorded in the memory element 304. The initial value of the high temperature error flag is OFF (for example, a numerical value such as "0" corresponding to OFF), and if a high temperature error occurs in the fixing unit 8, the value of the high temperature error flag is updated to ON (for example, a numerical value such as "1" corresponding to ON). In this embodiment, it is assumed that when the fuse 301 is not cut, it indicates that the high temperature error flag is OFF, and when the fuse 301 is cut, it indicates that the high temperature error flag is ON.

[0031] FIG. 3 is a diagram (circuit diagram) showing the detailed configuration of the memory circuit 9 and the memory control circuit 11. As shown in FIG.

[0032] The memory circuit 9 and the memory control circuit 11 are connected by two contacts 306 and 307 (two lines). Hereinafter, the contact 306 and the elements connected to the contact 306 side will be referred to as the "0 system", and the contact 307 and the elements connected to the contact 307 side will be referred to as the "1 system".

[0033] First, the configuration of the memory circuit 9 will be described.

[0034] In the memory circuit 9, in addition to a fuse 301 and a memory element 304, Zener diodes 303 and 305 and a resistor 302 are arranged.

[0035] 3, the memory element 304 is connected between a contact 306 and a contact 307. The memory element 304 can be configured, for example, by a two-wire memory (for example, a semiconductor memory chip) having two terminals 304a and 304b.

[0036] One end (cathodes) of the Zener diodes 303 and 305 is connected to contacts 306 and 307, respectively, and the other end (anodes) of the Zener diodes 303 and 305 is connected to one end of a fuse 301 via a resistor 302. The other end of the fuse 301 is grounded. In this embodiment, the fuse 301 is grounded to an apparatus body frame ground 317 via a fixing unit frame ground 318. The resistor 302 is a resistor (limiting resistor) that limits the power supply (current / voltage) flowing through the fuse 301.

[0037] In this embodiment, the Zener voltages (breakdown voltages) of the Zener diodes 303 and 305 are both set to the same voltage VZ.

[0038] Next, the configuration of the memory control circuit 11 will be described.

[0039] In the storage control circuit 11, the contacts 306 and 307 are connected to switching circuits 309 and 312 and voltage level detection circuits 310 and 313, respectively. The switching circuits 309 and 312 are also connected to power sources 308 and 311 via resistors 319 and 320, respectively. Furthermore, the switching circuits 309 and 312 are also connected to TAG signal lines 314 and 315.

[0040] The power supplies 308 and 311 are each capable of switching between a power supply voltage VCC and a power supply voltage VDD and applying them under the control of the control unit 2. The TAG signal lines 314 and 315 are each a signal line for transmitting a control signal from the control processing unit 10.

[0041] VCC is a voltage level used when checking the state (cut or not cut) of fuse 301 (hereinafter referred to as "fuse check"), and VDD is a voltage level used when cutting / melting fuse 301 (hereinafter referred to as "fuse cut"). Here, VCC is higher than Zener voltage VZ (VCC>VZ) and is a voltage at which fuse 301 will not cut when applied via Zener diodes 303 and 305. Also, here, VDD is higher than VCC (VDD>VCC) and is a voltage at which fuse 301 will cut when applied via Zener diodes 303 and 305.

[0042] The switching circuit 309 is a switching means for switching and connecting the contact 306 to either the power source 308 or the TAG signal line 314. The voltage level detection circuit 310 is a means for detecting the voltage level of the contact 306.

[0043] The switching circuit 312 is a switching means for switching and connecting either the power supply 311 or the TAG signal line 315 to the contact 307. The voltage level detection circuit 313 is a means for detecting the voltage level of the contact 307.

[0044] There is no limitation on the specific configuration of the switching circuits 309 and 312, and various switching methods (for example, switching circuits using various transistors, etc.) can be applied. In addition, there is no limitation on the specific configuration of the voltage level detection circuits 310 and 313, and various voltage detection means can be applied.

[0045] FIG. 4 is a diagram showing an example of a mounting structure of the memory circuit 9 in the fixing unit 8 (a perspective view of the fixing unit 8).

[0046] As shown in Fig. 4, a drawer connector 601 for connecting to the main body of the printer 1 via a cable, and a tag board 602 on which the memory control circuit 11 is mounted are disposed below the fixing unit 8. Also, as shown in Fig. 4, a contact connector 603 for contacting and connecting to the tag board 602 is disposed on the side of the main body of the printer 1.

[0047] FIG. 5 is a schematic diagram showing an expanded view of tag board 602.

[0048] As shown in FIG. 5, the tag board 602 is implemented with a memory circuit 9 including a fuse 301 and a memory element 304 .

[0049] 4 and 5, tag board 60r2 is provided with contactor 306a constituting contact 306 on the memory circuit 9 side, and contactor 307a constituting contact 307 on the memory circuit 9 side. Contact connector 603 is provided with contactor 306b constituting contact 306 on the memory control circuit 11 side, and contactor 307b constituting contact 307 on the memory control circuit 11. That is, contact 306 is formed by contact between contactor 306a and contactor 306b. Contact 307 is formed by contact between contactor 307a and contactor 307b.

[0050] (A-2) Operation of the embodiment Next, the operation of the printing device 1 will be described.

[0051] First, the operation of the storage control circuit 11 will be described with reference to FIG.

[0052] FIG. 6 is a diagram showing patterns of the switching states of the switching circuits 309 and 312 and the voltage levels of the power supplies 308 and 311 in the storage control circuit 11. In FIG.

[0053] Figure 6 shows the switching state patterns of the memory control circuit 11: a "normal state," a "fuse check state" that attempts to check the state of fuse 301 (either cut or uncut), and a "fuse cut state" that attempts to cut (melt) fuse 301.

[0054] The control processing unit 10 controls the voltage levels of the switching circuits 309 and 312 and the power supplies 308 and 311 in accordance with the pattern of FIG.

[0055] 6, when the control processor 10 controls the storage control circuit 11 to the "normal state", it switches the switching circuit 309 of system 0 to the TAG signal line 314 of system 0 (switching so as to connect the contact 306 of system 0 and the TAG signal line 314) and switches the switching circuit 312 of system 1 to the TAG signal line 315 of system 1 (switching so as to connect the contact 307 of system 1 and the TAG signal line 315 of system 1). In the normal state, the control processor 10 accesses the storage element 304 via the TAG signal lines 314 and 315, making it possible to read and write data.

[0056] As shown in FIG. 6, when the control processing unit 10 controls the storage control circuit 11 to be in the "fuse check state", the control processing unit 10 switches the switching circuit 309 of the 0 system to the power supply 308 of the 0 system (switches so as to connect the contact 306 of the 0 system to the power supply 308 of the 0 system) and switches the switching circuit 312 of the 1 system to the power supply 311 of the 1 system (switches so as to connect the contact 307 of the 1 system to the power supply 311 of the 1 system). In the fuse check state, the control processing unit 10 controls the power supply voltages of the power supply 308 of the 0 system and the power supply 311 of the 1 system to VCC. In the fuse check state, the control processing unit 10 can check the state (cut state or uncut state) of the fuse 301 based on the voltage level detected by the voltage level detection circuit 310 of the 0 system and the voltage level detected by the switching circuit 309 of the 1 system. Details of the fuse check by the control processing unit 10 will be described later.

[0057] Furthermore, as shown in FIG. 6, when the control processing unit 10 controls the storage control circuit 11 to the "fuse cut state", it switches the switching circuit 309 of the 0 system to the power supply 308 of the 0 system (switching so as to connect the contact 306 of the 0 system and the power supply 308 of the 0 system) and switches the switching circuit 312 of the 1 system to the power supply 311 of the 1 system (switching so as to connect the contact 307 of the 1 system and the power supply 311 of the 1 system). In the fuse cut state, the control processing unit 10 controls the power supply voltages of the power supply 308 of the 0 system and the power supply 311 of the 1 system to VDD. In the fuse cut state, a current of a predetermined value or more flows through the fuse 301, causing it to be cut (melted) and to enter the cut state. In other words, when the fuse is cut, if any of the contacts is in a normal (connected) state, the fuse 301 will be cut.

[0058] Next, the fuse check performed by the control processing unit 10 will be described in detail with reference to FIG.

[0059] FIG. 7 is a diagram showing the detection voltage level (the read value of the detection voltage level in the voltage level detection circuit 310 of the 0 system or the voltage level detection circuit 313 of the 1 system) for each combination of the state of the fuse 301 and the state of the contacts (contact 306 of the 0 system or contact 307 of the 1 system).

[0060] 7, the read values ​​of the detection voltage level are shown separately for the cases where the fuse 301 is in an uncut state and the case where it is in a cut state. Also, in FIG. 7, the read values ​​of the detection voltage level are shown separately for the cases where the contacts are in a normal state (connected state) and an abnormal state (open state). For example, if the contactor 306a and the contactor 307a are connected (conductive) in the contactor 306 of the 0 system, the contactor 306 of the 0 system can be said to be in a normal (connected) state. On the other hand, if the contactor 306a and the contactor 307a are not connected (conductive) in the contactor 306 of the 0 system for some reason (for example, if they are separated or in poor contact), the contactor 306 of the 0 system can be said to be in an abnormal (open) state.

[0061] 7, when fuse 301 is not cut and the contact state is normal (connected), the read value of the detection voltage level for that contact is VCC-VZ (the voltage level obtained by subtracting VZ from VCC). When fuse 301 is not cut and the contact state is abnormal (open), the read value of the detection voltage level for that contact is VCC. Furthermore, when fuse 301 is cut, the read value of the detection voltage level for that contact is VCC regardless of the contact state.

[0062] For example, when fuse 301 is not blown and contact 306 of system 0 is normal (connected), a current (current of voltage level VCC) from power supply 308 of system 0 flows from contact 306 of system 0 through Zener diode 303 to fuse 301. Therefore, in this case, the read value of the detected voltage level in voltage level detection circuit 310 of system 0 is VCC-VZ.

[0063] Also, for example, if the fuse 301 is not blown and the contact 306 of the 0 system is abnormal (open), the current from the power supply 308 of the 0 system (current with a voltage level of VCC) does not flow from the contact 306 of the 0 system to the Zener diode 303. Therefore, in this case, the read value of the detection voltage level at the contact 306 of the 0 system is VCC.

[0064] Furthermore, for example, when the fuse 301 is in a cut state, no current flows from either contact (contact 306 of system 0 and contact 307 of system 1) to the Zener diodes 303 and 305. Therefore, in this case, the read values ​​of the detection voltage levels at either contact (contact 306 of system 0 and contact 307 of system 1) are VCC.

[0065] From the above, when the detection voltage level of at least one of the contacts 306 of the 0 system or the contacts 307 of the 1 system is VCC-VZ during the fuse check, the fuse 301 is in an uncut state. Also, when the detection voltage levels of the contacts 306 of the 0 system and the contacts 307 of the 1 system are both VCC during the fuse check, the fuse 301 is in a cut state or both contacts (the contacts 306 of the 0 system and the contacts 307 of the 1 system) are in an abnormal (open) state. In other words, when the control processing unit 10 checks the fuse, if any of the contacts is in a normal (connected) state, it is possible to determine the state of the fuse 301. Note that when the fuse check is performed and both contacts are in an abnormal (open) state, the detection voltage levels of both are VCC even if the fuse 301 is not cut. However, in this embodiment, when the detection voltage levels of both are VCC, the control processing unit 10 considers the fuse 301 to be in a cut state.

[0066] Next, a process in which the control processing unit 10 controls the memory circuit 9 via the memory control circuit 11 will be described with reference to FIGS.

[0067] FIG. 8 is a flowchart showing an example of a process in which the control processing unit 10 checks the high temperature error flag at the time of startup.

[0068] Here, it is assumed that the power supply of the printing device 1 is turned on and the control unit 2 (control processing unit 10) is started (S101).

[0069] When the control processing unit 10 is started, it controls the memory control circuit 11 to the normal state, accesses the memory element 304 via the TAG signal lines 314, 315, and attempts to read data (data of the high temperature error flag) from the memory element 304 (S102).

[0070] The control processing unit 10 checks the result of reading the high temperature error flag from the storage element 304 (S103). If the control processing unit 10 succeeds in reading the data of the high temperature error flag and the read high temperature error flag is ON, the control processing unit 10 proceeds to step S107, which will be described later. If the control processing unit 10 fails to read the data from the storage element 304 or if the read high temperature error flag is OFF, the control processing unit 10 proceeds to step S104, which will be described later.

[0071] If data reading from the storage element 304 fails, or if the read high temperature error flag is OFF, the control processing unit 10 performs a fuse check (S104) and confirms the result (S105).

[0072] Specifically, the control processing unit 10 controls the memory control circuit 11 to enter a fuse check state, and checks the read values ​​of the detection voltage levels of the contact 306 of system 0 and the contact 307 of system 1 (detection voltage levels detected by the voltage level detection circuits 310, 313).

[0073] At this time, if the detected voltage level of at least either the contact 306 of the 0 system or the contact 307 of the 1 system is VCC-VZ, the control processing unit 10 determines that the fuse 301 is not cut (i.e., the high temperature error flag is OFF), and proceeds to step S106, which will be described later. Also, if the detected voltage levels of both the contact 306 of the 0 system and the contact 307 of the 1 system are VCC, the control processing unit 10 determines that the fuse 301 is cut (i.e., the high temperature error flag is ON), and proceeds to step S107, which will be described later.

[0074] If the result of the fuse check in step S105 is that the fuse is not cut, the control processing unit 10 controls the storage control circuit 11 to the normal state (S106) and continues operation.

[0075] On the other hand, if the result of the fuse check in step S105 is a blown state, or if the high temperature error flag is ON in step S103, the control processing unit 10 outputs a message indicating that an error has occurred in the fixing unit 8 (for example, performs an output process such as displaying that there is a fixing unit error on the display unit 4) (S107), and stops operation (S108).

[0076] FIG. 9 is a flowchart showing the operation performed when the control processing unit 10 detects a high temperature error in the fixing unit 8. As shown in FIG.

[0077] Here, it is assumed that the control processing unit 10 first detects that a high temperature error has occurred in the fixing unit 8 (S201). For example, the control processing unit 10 detects a high temperature error when a temperature detection process using the thermistor 171 detects that the temperature in the fixing unit 8 is equal to or higher than a predetermined temperature (high temperature error state).

[0078] Next, the control processing unit 10 controls the storage control circuit 11 to the normal state, attempts to access the storage element 304 via the TAG signal lines 314 and 315 (S202), and checks the result of the access (S203). If the control processing unit 10 successfully accesses the storage element 304, the process proceeds to step S204, which will be described later, and if not, the process proceeds to step S205, which will be described later.

[0079] If it is confirmed in step S203 that the access to the memory element 304 has been successful, the control processing unit 10 updates (writes) the treble error flag data in the memory element 304 to ON (S204), and proceeds to step S206 described below.

[0080] On the other hand, if it is confirmed in the above-mentioned step S203 that access to the memory element 304 has failed, the control processing unit 10 controls the memory control circuit 11 to a fuse cut state, cuts the fuse 301 (S205), and proceeds to step S206 described later.

[0081] On the other hand, when step S204 (updating the high temperature error flag to ON) or step S205 (cutting the fuse) is performed, the control processing unit 10 outputs a message indicating that an error has occurred in the fixing unit 8 (for example, outputting a message from the display unit 4 indicating that there is a fixing unit error) (S206), and stops operation (S207).

[0082] (A-3) Effects of the embodiment According to this embodiment, the following effects can be obtained.

[0083] In this embodiment, by arranging the fuse 301 and Zener diodes 303 and 305 between the memory element 304 and ground (the device body frame ground 317, the fuser frame ground 318), the fuse 301 can function as a management information recording medium without increasing the number of signal lines (TAG signal lines) (the number of contacts) between the main body of the printing device 1 and the fuser 8.

[0084] Furthermore, in this embodiment, a Zener diode is provided for each contact (each terminal of the storage element 304), so that if any of the contacts is in a normal (connected) state, it is possible to check and cut the fuse.

[0085] Furthermore, in this embodiment, since the fuse 301 is mounted on the tag board 602 (memory circuit 9) like the memory element 304, it is easy to secure a mounting location for the fuse 301.

[0086] Furthermore, in this embodiment, when checking or cutting a fuse, the same level of voltage is applied to each contact (contacts 306, 307), so that the voltage level between each terminal of memory element 304 can be kept the same, thereby protecting memory element 304.

[0087] (B) Other embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments such as those exemplified below.

[0088] (B-1) In the above embodiment, the configuration was described in which the memory circuit 9 as the memory device of the present invention is attached to the fixing unit 8 of the printing device 1 (image forming device), but the memory device of the present invention is not limited to the fixing unit of the image forming device, and may be attached to various components of various devices. For example, the memory device of the present invention may be attached to other components (e.g., image drum unit 117, etc.) in the image forming device. The memory device of the present invention may also be applied to mounted components of devices other than image forming devices. For example, the memory device of the present invention may be applied to mounted components such as a power supply unit mounted on a computer.

[0089] (B-2) In the above embodiment, a two-wire memory having two terminals 304a and 304b is applied as the storage element 304, but a memory other than the two-wire type (a memory having one wire or three or more wires) may be applied. For example, in the above embodiment, a set of a contact 306, a Zener diode 303, a power supply 308, a switching circuit 309, a voltage level detection circuit 310, a TAG signal line 314, and a resistor 319 is arranged for the terminal 304a of the storage element 304, but if the storage element 304 is a three-wire type having three terminals, the above set needs to be arranged for each terminal of the storage element 304. In other words, even if the storage element 304 is not a two-wire type, by arranging the above set for each terminal of the storage element 304, the same effect as the above embodiment can be achieved. Even if the memory element 304 is of a three-wire type or more, in the same manner as in the above embodiment, if any of the contacts is in a normal (connected) state when the fuse is cut, the fuse 301 is cut, and if any of the contacts is in a normal (connected) state when the fuse is checked, the state of the fuse 301 can be determined by the control processing unit 10. [Explanation of symbols]

[0090] 1...printing device, 2...control section, 3...communication section, 4...display section, 5...image forming section, 6...mechanism section, 7...image forming processing section, 8...fixing unit, 9...memory circuit, 10...control processing section, 11...memory control circuit, 301...fuse, 302...resistance, 303...zener diode, 304...memory element, 304a...terminal, 304b...terminal, 305...zener diode, 306...contact point, 306a...contact piece, 306b...connection Contact, 307...contact, 307a...contact, 307b...contact, 308...power source, 309...switching circuit, 310...voltage level detection circuit, 311...power source, 312...switching circuit, 313...voltage level detection circuit, 314...TAG signal line, 314...signal line, 315...signal line, 315...TAG signal line, 317...apparatus main body frame ground, 318...fixing unit frame ground, 319...resistor, 320...resistor

Claims

1. An image forming apparatus including a fixing device that fixes a developer image on a medium and a control unit, the fixing unit includes a storage device including a data recordable storage element, a contact between the control unit and the storage element, and a Zener diode having a Zener voltage as a first voltage and a fuse connected in series and disposed between the contact and ground; The control unit is a voltage level detection means for detecting a voltage level based on the voltage of the contact; When accessing the memory element through the contact, the memory element is controlled by an electrical signal having a voltage equal to or lower than the first voltage; when checking the state of the fuse, a second voltage which is equal to or higher than the first voltage and does not cause the fuse to break is applied to the contacts, and the state of the fuse is judged according to the voltage level detected by the voltage level detection means; When the fuse is to be cut, a third voltage at which the fuse is cut is applied to the contact via the Zener diode.

1. An image forming apparatus comprising:

2. the memory element comprises a first terminal and a second terminal, the contact comprises a first contact and a second contact, the Zener diode comprises a first Zener diode and a second Zener diode, and the voltage level sensing means comprises a first voltage level sensing means and a second voltage level sensing means; the first terminal is connected to the first contact between the control unit and the memory element, and the second terminal is connected to the second contact between the control unit and the memory element; The storage device has the first Zener diode connected between the first contact and the fuse, and the second Zener diode connected between the second contact and the fuse. The control unit is The first voltage level detection means is used to detect a voltage level based on a voltage at the first contact, and the second voltage level detection means is used to detect a voltage level based on a voltage at the second contact. When accessing the memory element via the first contact and the second contact, the memory element is controlled by an electrical signal having a voltage equal to or lower than the first voltage; when checking the state of the fuse, applying the second voltage to the first contact and the second contact, and judging the state of the fuse according to a first detection voltage level detected by the first voltage level detection means and a second detection voltage level detected by the second voltage level detection means; When the fuse is cut, the third voltage is applied to the first contact and the second contact.

2. The image forming apparatus according to claim 1,

3. 3. The image forming apparatus according to claim 2, wherein the control unit determines that the fuse is in an uncut state when at least one of the first detection voltage level or the second detection voltage level is a voltage obtained by subtracting the first voltage from the second voltage, and determines that the fuse is in a cut state when both the first detection voltage level and the second detection voltage level are the second voltage.

4. In a storage device included in a mounted component mounted on an apparatus, A memory element capable of storing data; a contact between the body of the device and the memory element; a Zener diode having a Zener voltage as a first voltage; a fuse connected in series with the Zener diode; The zener diode and the fuse are disposed between the contact and ground.

16. A storage device comprising:

5. 5. The storage device according to claim 4, wherein the device is an image forming device, and the mounted part is a fixing device that fixes a developer image on a medium in the image forming device.

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