1. A transmitting and receiving device comprising:
a transmitting device having
a plurality of sigma-delta analog-to-digital conversion units, provided corresponding in number to channels of input analog signals, which generate binary digital signals by performing sigma-delta analog-to-digital conversion for the analog signals,
a pulse width modulation encoder which generates a pulse width signal having a pulse width corresponding to the binary digital signals outputted from the plurality of sigma-delta analog-to-digital conversion units, and
a light-emitting element drive unit which generates and transmits an optical signal by causing a light-emitting element to emit light on the basis of the pulse width signal; and
a receiving device having
an optical reception unit which converts a current signal, obtained by receiving the optical signal by a light-receiving element, into the pulse width signal,
a pulse width demodulation decoder which reconstructs the binary digital signals of a plurality of channels on the basis of the pulse width signal, and
a plurality of 1-bit digital-to-analog conversion units, provided corresponding in number to the channels of the binary digital signals, which reconstruct the analog signals by performing 1-bit digital-to-analog conversion for the input binary digital signals.
2. The transmitting and receiving device according to claim 1, wherein the pulse width modulation encoder comprises
a pulse width signal generator having
a (2N+1)-stage flip-flop obtained by series-connecting 2N+1 flip-flops, where N is the number of channels, and
2N AND circuits which generate 2N types of pulse width signals with different pulse widths, each being the pulse width signal, by calculating a logical product of an output of the flip-flop at a first stage and each of inverted outputs of the flip-flops at second to last stages, and
a selection circuit which selects and outputs a desired one of the 2N types of pulse width signals in accordance with the binary digital signals outputted from the plurality of sigma-delta analog-to-digital conversion units.
3. The transmitting and receiving device according to claim 1, wherein the light-emitting element drive unit comprises
a current supply unit which is series-connected to the light-emitting element and supplies a current to the light-emitting element and
a switching unit which switches a state of supply of a current to the light-emitting element by the current supply unit,
the switching unit has
a diode connected to an anode of the light-emitting element such that a direction heading from the anode of the light-emitting element to a cathode becomes a forward direction and
a switching element which is series-connected to the diode and switches a connection state on the basis of the pulse width signal, and
a voltage drop in a current path formed of the diode and switching element when the switching element is brought into a conducting state is selected to be smaller than a forward voltage when the light-emitting element is emitting light.
4. The transmitting and receiving device according to claim 3, wherein the light-emitting element drive unit further comprises
a peaking unit which supplies a peaking current in the forward direction of the light-emitting element if the switching element is brought into a non-conducting state and supplies a peaking current in a direction opposite to the forward direction of the light-emitting element if the switching element is brought into the conducting state.
5. The transmitting and receiving device according to claim 4, wherein the peaking unit is connected to the anode of the light-emitting element and composed of a series circuit of an inverter, a capacitor, and a resistor.
6. The transmitting and receiving device according to claim 1, wherein each of the sigma-delta analog-to-digital conversion units has an auto-zero integrator as an integrator.
7. The transmitting and receiving device according to claim 1, wherein the optical reception unit comprises
an amplifier which generates a positive-phase voltage signal and a negative-phase voltage signal on the basis of a current signal obtained by the light-receiving element and outputs the signals,
a peak hold circuit which generates a peak voltage signal by detecting and holding a peak voltage of the positive-phase voltage signal,
a group of resistive elements which generates first and second voltage signals that are equal in amplitude and whose waveforms cross each other in the neighborhood of centers of amplitudes of the first and second voltage signals on the basis of the positive-phase voltage signal, negative-phase voltage signal, and peak voltage signal, and
a comparator which generates the pulse width signal by comparing the first and second voltage signals.
8. The transmitting and receiving device according to claim 7, wherein the peak hold circuit has a peak detector, a diode, and a capacitor.
9. The transmitting and receiving device according to claim 7, wherein the group of resistive elements is formed by
a first resistor connected between an output end of the peak hold circuit and a second input end of the comparator,
a second resistor connected between a second output end of the amplifier and the second input end of the comparator,
a third resistor connected between a first output end of the amplifier and a first input end of the comparator, and
a fourth resistor connected between the second output end of the amplifier and the first input end of the comparator, and
resistance values of the first and second resistors are selected such that the resistance values have a ratio of 1:1, and resistance values of the third and fourth resistors are selected such that the resistance values have a ratio of 1:3.
10. The transmitting and receiving device according to claim 1, further comprising
a plurality of low-pass filters respectively connected to subsequent stages of the plurality of 1-bit digital-to-analog conversion units, wherein
each of the low-pass filters includes an active filter, and a chopper amplifier which operates in accordance with a reproduced clock signal is used as an amplifier of the active filter.
11. A transmitting device comprising:
a plurality of sigma-delta analog-to-digital conversion units, provided corresponding in number to channels of input analog signals, which generate binary digital signals by performing sigma-delta analog-to-digital conversion for the analog signals;
a pulse width modulation encoder which generates a pulse width signal having a pulse width corresponding to the binary digital signals output from the plurality of sigma-delta analog-to-digital conversion units; and
a light-emitting element drive unit which generates and transmits an optical signal by causing a light-emitting element to emit light on the basis of the pulse width signal.
12. The transmitting device according to claim 11, wherein the pulse width modulation encoder comprises
a pulse width signal generator having
a (2N+1)-stage flip-flop obtained by series-connecting 2N+1 flip-flops, where N is the number of channels, and
2N AND circuits which generate 2N types of pulse width signals with different pulse widths, each being the pulse width signal, by calculating a logical product of an output of the flip-flop at a first stage and each of inverted outputs of the flip-flops at second to last stages; and
a selection circuit which selects and outputs a desired one of the 2N types of pulse width signals in accordance with the binary digital signals output from the plurality of sigma-delta analog-to-digital conversion units.
13. The transmitting device according to claim 11, wherein the light-emitting element drive unit comprises
a current supply unit which is series-connected to the light-emitting element and supplies a current to the light-emitting element and
a switching unit which switches a state of supply of a current to the light-emitting element by the current supply unit,
the switching unit has
a diode connected to an anode of the light-emitting element such that a direction heading from the anode of the light-emitting element to a cathode becomes a forward direction and
a switching element which is series-connected to the diode and switches a connection state on the basis of the pulse width signal, and
a voltage drop in a current path formed of the diode and switching element when the switching element is brought into a conducting state is selected to be smaller than a forward voltage when the light-emitting element is emitting light.
14. The transmitting device according to claim 13, wherein the light-emitting element drive unit further comprises a peaking unit which supplies a peaking current in the forward direction of the light-emitting element if the switching element is brought into a non-conducting state and supplies a peaking current in a direction opposite to the forward direction of the light-emitting element if the switching element is brought into the conducting state.
15. The transmitting device according to claim 14, wherein the peaking unit is connected to the anode of the light-emitting element and composed of a series circuit of an inverter, a capacitor, and a resistor.
16. The transmitting device according to claim 11, wherein each of the sigma-delta analog-to-digital conversion units has an auto-zero integrator as an integrator.
17. A receiving device comprising:
an optical reception unit which converts a current signal, obtained by receiving an optical signal by a light-receiving element, into a pulse width signal;
a pulse width demodulation decoder which reconstructs binary digital signals of a plurality of channels on the basis of the pulse width signal; and
a plurality of 1-bit digital-to-analog conversion units, provided corresponding in number to the channels of the binary digital signals, which reconstruct analog signals by performing 1-bit digital-to-analog conversion for the input binary digital signals.
18. The receiving device according to claim 17, wherein the optical reception unit comprises
an amplifier which generates a positive-phase voltage signal and a negative-phase voltage signal on the basis of a current signal obtained by the light-receiving element and outputs the signals,
a peak hold circuit which generates a peak voltage signal by detecting and holding a peak voltage of the positive-phase voltage signal,
a group of resistive elements which generates first and second voltage signals that are equal in amplitude and whose waveforms cross each other in the neighborhood of centers of amplitudes of the first and second voltage signals on the basis of the positive-phase voltage signal, negative-phase voltage signal, and peak voltage signal, and
a comparator which generates the pulse width signal by comparing the first and second voltage signals.
19. The receiving device according to claim 18, wherein the peak hold circuit has a peak detector, a diode, and a capacitor.
20. The receiving device according to claim 18, wherein the group of resistive elements is formed by
a first resistor connected between an output end of the peak hold circuit and a second input end of the comparator,
a second resistor connected between a second output end of the amplifier and the second input end of the comparator,
a third resistor connected between a first output end of the amplifier and a first input end of the comparator, and
a fourth resistor connected between the second output end of the amplifier and the first input end of the comparator, and
resistance values of the first and second resistors are selected such that the resistance values have a ratio of 1:1, and resistance values of the third and fourth resistors are selected such that the resistance values have a ratio of 1:3.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus having a guide member, comprising:
a cartridge frame;
an electrophotographic photosensitive drum;
a process unit acting on the electrophotographic photosensitive drum; and
a projecting portion in the cartridge frame,
wherein, when said process cartridge is mounted to the main body of the electrophotographic image forming apparatus, said projecting portion is guided by the guide member to guide said process cartridge in a mounting direction in which said process cartridge is mounted to the main body of the electrophotographic image forming apparatus,
wherein, when said process cartridge is mounted to the main body of an electrophotographic image forming apparatus which conforms to functions of said process cartridge, said projecting portion allows said process cartridge to be inserted in the main body of the electrophotographic image forming apparatus that conforms to the functions of said process cartridge, and,
wherein, when said process cartridge is mounted to a main body of an electrophotographic image forming apparatus which does not conform to the functions of said process cartridge and has different functions, said projecting portion abuts against a main body frame in the main body of the electrophotographic image forming apparatus having the different functions to prevent mounting of said process cartridge,
wherein said projecting portion is provided so as to project downward from said cartridge frame, and when said process cartridge is withdrawn from the main body of the electrophotographic image forming apparatus to be mounted on a mounting surface, said projecting portion maintains a stable posture of said process cartridge.
2. A process cartridge according to claim 1,
wherein said projecting portion comprises:
a first projecting portion provided on one end side of said cartridge frame in a longitudinal direction of said process cartridge and, when said process cartridge is mounted to the main body of the electrophotographic image forming apparatus, said first projecting portion abuts against the guide member; and
a second projecting portion provided on another end side of said cartridge frame in the longitudinal direction and, when said process cartridge is mounted to the main body of the electrophotographic image forming apparatus, said second projecting portion abuts against the guide member, and
wherein, when said process cartridge is mounted to the main body of the electrophotographic image forming apparatus which does not conform to the functions of the process cartridge and has different functions, at least one of said first projecting portion and said second projecting portion abuts against the main body frame in the main body of the electrophotographic image forming apparatus having the different functions to prevent said process cartridge from being mounted thereto.
3. An electrophotographic image forming apparatus for forming an image on a recording medium, wherein a process cartridge is detachably mountable to a main body of said electrophotographic image forming apparatus, said electrophotographic image forming apparatus, comprising:
(i) a guide member;
(ii) a mounting unit which is configured and positioned to detachably mount the process cartridge, the process cartridge comprising: a cartridge frame; an electrophotographic photosensitive drum; a process unit acting on the electrophotographic photosensitive drum; and a projecting portion which is provided in the cartridge frame and, when the process cartridge is mounted to the main body of said electrophotographic image forming apparatus, the projecting portion is guided by said guide member to guide the process cartridge in a mounting direction in which the process cartridge is mounted to the main body of said electrophotographic image forming apparatus, wherein, when the process cartridge is mounted to the main body of an electrophotographic image forming apparatus which conforms to functions of the process cartridge, the projecting portion allows the process cartridge to be inserted in the main body of the electrophotographic image forming apparatus conforming to the functions of the process cartridge and, when the process cartridge is mounted to a main body of an electrophotographic image forming apparatus which does not conform to the functions of the process cartridge and has different functions, the projecting portion abuts against a main body frame provided in the main body of the electrophotographic image forming apparatus having the different functions to prevent mounting of the process cartridge, the projecting portion being provided so as to project downward from the cartridge frame, and
when the process cartridge is withdrawn from the main body of said electrophotographic image forming apparatus to be mounted on a mounting surface, the projecting portion and said main body maintain a stable posture of the process cartridge; and
(iii) a conveying unit which conveys the recording medium.
4. An electrophotographic image forming apparatus according to claim 3,
wherein the electrophotographic image forming apparatus that conforms to the functions of the process cartridge is different from the electrophotographic image forming apparatus having the different functions in the speed for forming an image on the recording medium.
5. A process cartridge mounting system which detachably mounts a process cartridge to an electrophotographic image forming apparatus, wherein a main body of the electrophotographic image forming apparatus comprises a guide member,
said mounting system comprising a mounting unit configured and positioned to mount the process cartridge to the electrophotographic image forming apparatus, the process cartridge comprising a cartridge frame, an electrophotographic photosensitive drum, a process unit acting on the electrophotographic photosensitive drum, and a projecting portion provided in the cartridge frame and, when said mounting unit mounts the process cartridge to the main body of the electrophotographic image forming apparatus, the projecting portion is guided by the guide member to guide the process cartridge in a mounting direction in which the process cartridge is mounted to the main body of the electrophotographic image forming apparatus, wherein: when the process cartridge is mounted to a main body of an electrophotographic image forming apparatus which does not conform to functions of the process cartridge and has different functions therefrom, the projecting portion abuts against a main body frame provided in the main body of the electrophotographic image forming apparatus having the different functions to prevent mounting of the process cartridge, the projecting portion being provided so as to project downward from the cartridge frame, and when the process cartridge is withdrawn from the main body of the electrophotographic image forming apparatus to be mounted on a mounting surface, the projecting portion maintains a stable posture of the process cartridge,
when the process cartridge is mounted to the main body of an electrophotographic image forming apparatus which does not conform to functions of the process cartridge and has different functions, the main body frame in the main body of the electrophotographic image forming apparatus having the different functions and the projecting portion abut against each other to prevent mounting of the process cartridge, and
when the process cartridge is mounted to the main body of the electrophotographic image forming apparatus which conforms to the functions of the process cartridge, the projecting portion is guided in the mounting direction by the guide member, and the process cartridge is mounted to the main body of the electrophotographic image forming apparatus which conforms to the functions of the process cartridge by said mounting unit.
6. A process cartridge mounting system according to claim 5,
wherein the projecting portion comprises:
a first projecting portion which is provided on one end side of the cartridge frame in a longitudinal direction of the process cartridge and, when said mounting unit mounts the process cartridge to the main body of the electrophotographic image forming apparatus, the first projecting portion abuts against the guide member; and
a second projecting portion which is provided on another end side of the cartridge frame in the longitudinal direction and, when said mounting unit mounts the process cartridge to the main body of the electrophotographic image forming apparatus, the second projecting portion abuts against the guide member, and
wherein, when the process cartridge is mounted to the main body of the electrophotographic image forming apparatus which does not conform to the functions of the process cartridge and has different functions, at least one of the first projecting portion and the second projecting portion abuts against the main body frame provided in the main body of the electrophotographic image forming apparatus having the different functions to prevent the process cartridge from being mounted thereto.
7. A process cartridge mounting system according to claim 5 or 6,
wherein the electrophotographic image forming apparatus that conforms to the functions of the process cartridge is different from the electrophotographic image forming apparatus having the different functions in the speed for forming an image on recording medium.
8. A process cartridge detachably mountable to a main body of an electrophotographic image forming apparatus having a guide member, comprising:
an electrophotographic photosensitive drum;
a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum;
a cleaning frame configured and positioned to support said electrophotographic photosensitive drum;
a toner development frame configured and positioned to support said developing roller; and
a holder member which is provided at one longitudinal end of said process cartridge and connects said cleaning frame and said toner development frame,
wherein said holder member has a projecting portion,
wherein, when said process cartridge is withdrawn from the main body of the electrophotographic image forming apparatus to be mounted on a mounting surface, said projecting portion maintains a stable posture of said process cartridge,
wherein, when said process cartridge is mounted to the main body of the electrophotographic image forming apparatus, said projecting portion is guided by the guide member to guide said process cartridge, and
wherein, when said process cartridge is mounted to a main body of an electrophotographic image forming apparatus which does not conform to the functions of the process cartridge and has different functions therefrom, said projecting portion abuts against a main body frame provided in the main body of the electrophotographic image forming apparatus having different functions at a position such that an openclose cover, which closes an opening provided in the main body of the electrophotographic image forming apparatus having different functions, cannot close, to prevent said process cartridge from being inserted into the opening in the main body of the electrophotographic image forming apparatus having the different functions.
9. A process cartridge according to claim 8, wherein said holder member is provided at an one longitudinal end and the other longitudinal end of said process cartridge.
10. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising:
(i) a guide member;
(ii) mounting means for detachably mounting a process cartridge, the process cartridge comprising an electrophotographic photosensitive drum, a developing roller developing an electrostatic latent image formed on the electrophotographic photosensitive drum, a cleaning frame supporting the electrophotographic photosensitive drum, a toner development frame supporting the developing roller, and a holder member which is provided at one longitudinal end of the process cartridge and connects the cleaning frame and the toner development frame, wherein the holder member has a projecting portion, wherein, when the process cartridge is withdrawn from the main body of said electrophotographic image forming apparatus to be mounted on a mounting surface, the projecting portion maintains a stable posture of the process cartridge, wherein, when said mounting means mounts the process cartridge to the main body of said electrophotographic image forming apparatus, the projecting portion is guided by the guide member to guide the process cartridge, and wherein when the process cartridge is mounted to a main body of an electrophotographic image forming apparatus which does not conform to functions of the process cartridge and has different functions therefrom, the projecting portion abuts against a main body frame provided in the main body of the electrophotographic image forming apparatus having the different functions at a position such that an openclose cover, which closes an opening provided in the main body of the electrophotographic image forming apparatus having different functions, cannot close, to prevent the process cartridge from being inserted into the opening in the main body of the electrophotographic image forming apparatus having the different functions; and
(iii) conveying means for conveying the recording medium.